[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"minerals:one:1720":3},{"id":4,"longid":5,"guid":6,"name":7,"shortcode_ima":8,"entrytype":9,"entrytype_text":10,"varietyof":11,"synid":11,"polytypeof":11,"groupid":12,"weighting":13,"nolocadd":14,"blacklisted":14,"mindat_formula":8,"mindat_formula_note":11,"ima_formula":8,"elements":15,"sigelements":16,"key_elements":17,"impurities":18,"cim":19,"ima_status":20,"ima_notes":11,"ima_history":11,"approval_year":11,"publication_year":11,"discovery_year":11,"strunz10ed1":23,"strunz10ed2":24,"strunz10ed3":24,"strunz10ed4":25,"dana8ed1":23,"dana8ed2":23,"dana8ed3":23,"dana8ed4":23,"csystem":26,"cclass":27,"spacegroup":28,"spacegroupset":29,"a":30,"b":29,"c":29,"alpha":29,"beta":29,"gamma":29,"aerror":11,"berror":11,"cerror":11,"alphaerror":11,"betaerror":11,"gammaerror":11,"va3":11,"z":31,"csmetamict":14,"commentcrystal":11,"twinning":32,"tranglide":11,"parting":11,"epitaxidescription":11,"morphology":33,"tlform":11,"hmin":34,"hmax":35,"hardtype":35,"vhnmin":36,"vhnmax":37,"vhnerror":11,"vhng":38,"vhns":11,"commenthard":11,"dmeas":39,"dmeas2":40,"dcalc":41,"dmeaserror":11,"dcalcerror":11,"commentdense":42,"lustre":43,"lustretype":43,"commentluster":11,"diapheny":44,"streak":45,"colour":46,"commentcolor":11,"colors":47,"streak_colors":52,"luminescence":53,"uv":54,"cleavage":53,"cleavagetype":55,"fracturetype":56,"tenacity":57,"commentbreak":11,"opticaltype":58,"opticalsign":11,"opticalalpha":29,"opticalalpha2":29,"opticalalphaerror":11,"opticalbeta":29,"opticalbeta2":29,"opticalbetaerror":11,"opticalgamma":29,"opticalgamma2":29,"opticalgammaerror":11,"opticalomega":29,"opticalomega2":29,"opticalomegaerror":11,"opticalepsilon":29,"opticalepsilon2":29,"opticalepsilonerror":11,"opticaln":29,"opticaln2":29,"opticalnerror":11,"optical2vcalc":29,"optical2vcalc2":29,"optical2vcalcerror":11,"optical2vmeasured":29,"optical2vmeasured2":29,"optical2vmeasurederror":11,"rimin":11,"rimax":11,"opticaldispersion":11,"opticalpleochroism":59,"opticalpleochorismdesc":11,"opticalbirefringence":11,"opticalcomments":60,"opticalcolour":61,"opticalinternal":54,"opticaltropic":58,"opticalanisotropism":11,"opticalbireflectance":11,"opticalextinction":11,"opticalr":62,"specdispm":11,"ir":11,"electrical":11,"magnetism":11,"thermalbehaviour":63,"other":64,"industrial":65,"occurrence":11,"otheroccurrence":66,"type_specimen_store":11,"description_short":67,"aboutname":68,"rock_parent":11,"rock_parent2":11,"rock_root":9,"rock_bgs_code":11,"meteoritical_code":11,"updttime":69,"reviewed_at":11,"variety_of":11,"varieties":70,"group_members":85,"associates":108,"confused_with":295,"type_localities":296,"occurrence_total":297,"citations":298,"images":519,"structures":1337,"synonyms":1360,"language_names":1414,"wikidata_qid":1497,"texts":1498},1720,"1:1:1720:2","d732bdf3-ca18-4058-8314-f9a730a8ad7e","Native Gold","Au",0,"mineral",null,32720,95865,false,[8],[8],[8],"Ag,Cu,Pd,Hg, Bi","1.5",[21,22],"APPROVED","GRANDFATHERED","1","A","05","Isometric",32,224,"0","4.0786",4,"Common on (111) to give herringbone twins. Repeated on (111) to give stacks of spinel twins that form hexagonal wires.","Usually crude to rounded octahedra, cubes, and dodecahedra to 2 cm. Often elongated along [100] or [111] directions, forming herringbone and dendritic twins. Flattened {111} plates with triangular octahedral faces. Rarely as wires ([111] elongation); reticulated; dendritic; arborescent; filiform; spongy; also massive in rounded fragments, flattened grains and scales (gold dust).",2.5,3,"30","34",10,"15","19.3","19.309","Calculated density at 0° C. Depends on silver content (pure gold is 19.3).","Metallic","Opaque","Shining yellow","Rich yellow, paling to whitish-yellow with increasing silver; blue & green in transmitted light (only thinnest folia [gold leaf])",[48,49,50,51],"yellow","white","blue","green",[48],"None","none","None Observed","Hackly","malleable","Isotropic","Non-pleochroic","Reflectivity from Criddle & Stanley (1993)","Yellow to white with increasing silver, reddish with copper","(36.8,25.8) 400,\r\n(36.8,25.8) 420,\r\n(36.5,25.9) 440,\r\n(36.1,26.0) 460,\r\n(36.0,26.5) 470,\r\n(36.7,27.8) 480,\r\n(45.3,37.9) 500,\r\n(62.5,55.9) 520,\r\n(74.0,69.1) 540,\r\n(77.0,71.5) 546,\r\n(82.2,77.0) 560,\r\n(86.8,82.3) 580,\r\n(88.2,84.1) 589,\r\n(89.7,85.9) 600,\r\n(91.9,88.7) 620,\r\n(93.3,90.3) 640,\r\n(93.8,91.0) 650,\r\n(94.1,91.8) 660,\r\n(94.8,92.5) 680,\r\n(95.3,93.2) 700","Melting Point: 1062.4° ± 0.8°","Completely soluble with copper. Insoluble in acids except for aqua regia, with incomplete separation if more than 20% of silver is present.\r\n\r\nReported as spongy alteration pseudomorphs after calaverite (Cripple Creek).","Electrical conductor, transparent reflective coating, jewelry, dentistry, coinage, decorative coatings","1) Primary hydrothermal veins\r\n2) Volcanic-exhalative sulphide deposits\r\n3) Alluvial and eluvial","Copper Group. Gold-Silver Series and Gold-Palladium Series.\r\n\r\nThe name \"Native Gold\" is preferred here to avoid confusion although the formal IMA name remains simply \"gold\".\r\n\r\nA native element and precious metal, gold has long been prized for its bea...","Gold is one of the first minerals used by prehistoric cultures. The Latin name for this mineral was \"aurum\" and Jöns Jakob Berzelius used Au to represent the element when he established the current system of chemical symbols. The Old English word \"gold\" first appeared in written form about 725 and may further have been derived from \"gehl\" or \"jehl\". May be derived from Anglo-Saxon \"gold\" = yellow. (Known to alchemists as Sol.)","2025-11-29 17:32:00",[71,77,82],{"id":72,"name":73,"entrytype":74,"csystem":26,"ima_formula":11,"mindat_formula":75,"hmin":34,"hmax":35,"dmeas":11,"dcalc":11,"primary_image_id":76},1365,"Electrum",2,"(Au,Ag)",53179,{"id":78,"name":79,"entrytype":74,"csystem":11,"ima_formula":11,"mindat_formula":80,"hmin":11,"hmax":11,"dmeas":29,"dcalc":29,"primary_image_id":81},11037,"Palladium-bearing Gold","(Au,Pd)",72417,{"id":83,"name":84,"entrytype":74,"csystem":11,"ima_formula":11,"mindat_formula":80,"hmin":11,"hmax":11,"dmeas":29,"dcalc":11,"primary_image_id":11},10923,"Porpezite",[86,94,101],{"id":87,"name":88,"entrytype":9,"csystem":26,"ima_formula":89,"mindat_formula":89,"hmin":90,"hmax":74,"dmeas":91,"dcalc":92,"primary_image_id":93},2553,"Maldonite","Au\u003Csub>2\u003C\u002Fsub>Bi",1.5,"15.46","15.70",15215,{"id":95,"name":96,"entrytype":9,"csystem":26,"ima_formula":97,"mindat_formula":97,"hmin":34,"hmax":35,"dmeas":98,"dcalc":99,"primary_image_id":100},1209,"Native Copper","Cu","8.94","8.93",17148,{"id":102,"name":103,"entrytype":9,"csystem":26,"ima_formula":104,"mindat_formula":104,"hmin":34,"hmax":35,"dmeas":105,"dcalc":106,"primary_image_id":107},3664,"Native Silver","Ag","10.1","10.497",17318,[109,117,124,134,141,148,157,166,174,181,188,195,202,208,214,221,228,235,243,250,256,261,266,274,281,289],{"id":110,"name":111,"entrytype":9,"csystem":112,"ima_formula":113,"mindat_formula":113,"hmin":74,"hmax":34,"dmeas":114,"dcalc":115,"primary_image_id":116},63,"Aikinite","Orthorhombic","CuPbBiS\u003Csub>3\u003C\u002Fsub>","7.06","7.255",429,{"id":118,"name":119,"entrytype":9,"csystem":120,"ima_formula":121,"mindat_formula":121,"hmin":34,"hmax":34,"dmeas":29,"dcalc":122,"primary_image_id":123},108,"Aleksite","Trigonal","PbBi\u003Csub>2\u003C\u002Fsub>Te\u003Csub>2\u003C\u002Fsub>S\u003Csub>2\u003C\u002Fsub>","7.80",590,{"id":125,"name":126,"entrytype":9,"csystem":127,"ima_formula":128,"mindat_formula":129,"hmin":130,"hmax":130,"dmeas":131,"dcalc":132,"primary_image_id":133},134,"Alloclasite","Monoclinic","CoAsS","Co\u003Csub>1-x\u003C\u002Fsub>Fe\u003Csub>x\u003C\u002Fsub>AsS",5,"5.95","6.188",814,{"id":135,"name":136,"entrytype":9,"csystem":26,"ima_formula":137,"mindat_formula":137,"hmin":74,"hmax":35,"dmeas":138,"dcalc":139,"primary_image_id":140},147,"Altaite","PbTe","8.19","8.27",904,{"id":142,"name":143,"entrytype":9,"csystem":26,"ima_formula":144,"mindat_formula":145,"hmin":146,"hmax":146,"dmeas":29,"dcalc":147,"primary_image_id":11},319,"Argentotennantite-(Zn)","Ag\u003Csub>6\u003C\u002Fsub>(Cu\u003Csub>4\u003C\u002Fsub>Zn\u003Csub>2\u003C\u002Fsub>)As\u003Csub>4\u003C\u002Fsub>S\u003Csub>13\u003C\u002Fsub>","Ag\u003Csub>6\u003C\u002Fsub>(Cu\u003Csub>4\u003C\u002Fsub>Zn\u003Csub>2\u003C\u002Fsub>)As\u003Csub>4\u003C\u002Fsub>S\u003Csub>12\u003C\u002Fsub>S",3.5,"5.05",{"id":149,"name":150,"entrytype":9,"csystem":151,"ima_formula":152,"mindat_formula":152,"hmin":153,"hmax":153,"dmeas":154,"dcalc":155,"primary_image_id":156},301,"Arsenohauchecornite","Tetragonal","Ni\u003Csub>18\u003C\u002Fsub>Bi\u003Csub>3\u003C\u002Fsub>AsS\u003Csub>16\u003C\u002Fsub>",5.5,"6.35","6.52",2053,{"id":158,"name":159,"entrytype":9,"csystem":160,"ima_formula":161,"mindat_formula":162,"hmin":31,"hmax":31,"dmeas":163,"dcalc":164,"primary_image_id":165},303,"Arsenopalladinite","Triclinic","Pd\u003Csub>8\u003C\u002Fsub>As\u003Csub>3\u003C\u002Fsub>","Pd\u003Csub>8\u003C\u002Fsub>(As,Sb)\u003Csub>3\u003C\u002Fsub>","10.40","11.028",2080,{"id":167,"name":168,"entrytype":9,"csystem":127,"ima_formula":169,"mindat_formula":169,"hmin":153,"hmax":170,"dmeas":171,"dcalc":172,"primary_image_id":173},305,"Arsenopyrite","FeAsS",6,"6.07","6.18",29154,{"id":175,"name":176,"entrytype":9,"csystem":26,"ima_formula":177,"mindat_formula":177,"hmin":146,"hmax":146,"dmeas":178,"dcalc":179,"primary_image_id":180},423,"Auricupride","Cu\u003Csub>3\u003C\u002Fsub>Au","11.5","13.77",2329,{"id":182,"name":183,"entrytype":9,"csystem":26,"ima_formula":184,"mindat_formula":184,"hmin":35,"hmax":35,"dmeas":185,"dcalc":186,"primary_image_id":187},430,"Aurostibite","AuSb\u003Csub>2\u003C\u002Fsub>","9.98","9.91",2347,{"id":189,"name":190,"entrytype":9,"csystem":26,"ima_formula":191,"mindat_formula":191,"hmin":130,"hmax":130,"dmeas":192,"dcalc":193,"primary_image_id":194},439,"Awaruite","Ni\u003Csub>3\u003C\u002Fsub>Fe","7.8","7.74",2385,{"id":196,"name":197,"entrytype":9,"csystem":26,"ima_formula":198,"mindat_formula":198,"hmin":74,"hmax":74,"dmeas":199,"dcalc":200,"primary_image_id":201},645,"Berzelianite","Cu\u003Csub>2-x\u003C\u002Fsub>Se (x ≈ 0.12)","6.71","7.28",3181,{"id":203,"name":204,"entrytype":9,"csystem":26,"ima_formula":205,"mindat_formula":205,"hmin":34,"hmax":35,"dmeas":192,"dcalc":206,"primary_image_id":207},1061,"Clausthalite","PbSe","8.275",29490,{"id":209,"name":210,"entrytype":9,"csystem":120,"ima_formula":211,"mindat_formula":211,"hmin":74,"hmax":74,"dmeas":212,"dcalc":213,"primary_image_id":11},1368,"Ellisite","Tl\u003Csub>3\u003C\u002Fsub>AsS\u003Csub>3\u003C\u002Fsub>","7.10","7.18",{"id":215,"name":216,"entrytype":9,"csystem":151,"ima_formula":217,"mindat_formula":217,"hmin":35,"hmax":31,"dmeas":218,"dcalc":219,"primary_image_id":220},1451,"Famatinite","Cu\u003Csub>3\u003C\u002Fsub>SbS\u003Csub>4\u003C\u002Fsub>","4.635","4.66",8313,{"id":222,"name":223,"entrytype":9,"csystem":26,"ima_formula":224,"mindat_formula":224,"hmin":34,"hmax":34,"dmeas":225,"dcalc":226,"primary_image_id":227},1641,"Galena","PbS","7.60","7.57",9582,{"id":229,"name":230,"entrytype":9,"csystem":112,"ima_formula":231,"mindat_formula":231,"hmin":34,"hmax":146,"dmeas":232,"dcalc":233,"primary_image_id":234},1642,"Galenobismutite","PbBi\u003Csub>2\u003C\u002Fsub>S\u003Csub>4\u003C\u002Fsub>","6.9","7.195",9589,{"id":236,"name":237,"entrytype":9,"csystem":26,"ima_formula":238,"mindat_formula":239,"hmin":35,"hmax":146,"dmeas":240,"dcalc":241,"primary_image_id":242},1721,"Goldfieldite","(Cu\u003Csub>4\u003C\u002Fsub>◻\u003Csub>2\u003C\u002Fsub>)Cu\u003Csub>6\u003C\u002Fsub>Te\u003Csub>4\u003C\u002Fsub>S\u003Csub>13\u003C\u002Fsub>","(Cu\u003Csub>4\u003C\u002Fsub>◻\u003Csub>2\u003C\u002Fsub>)(Cu\u003Csub>4\u003C\u002Fsub>Cu\u003Csup>+\u003C\u002Fsup>\u003Csub>2\u003C\u002Fsub>)Te\u003Csub>4\u003C\u002Fsub>S\u003Csub>12\u003C\u002Fsub>S","4.95","4.935",10152,{"id":244,"name":245,"entrytype":9,"csystem":127,"ima_formula":246,"mindat_formula":246,"hmin":153,"hmax":170,"dmeas":247,"dcalc":248,"primary_image_id":249},1766,"Gudmundite","FeSbS","6.72","6.95",10554,{"id":251,"name":252,"entrytype":9,"csystem":151,"ima_formula":253,"mindat_formula":253,"hmin":130,"hmax":130,"dmeas":154,"dcalc":254,"primary_image_id":255},1829,"Hauchecornite","Ni\u003Csub>9\u003C\u002Fsub>BiSbS\u003Csub>8\u003C\u002Fsub>","6.58",10903,{"id":257,"name":258,"entrytype":9,"csystem":26,"ima_formula":259,"mindat_formula":259,"hmin":170,"hmax":260,"dmeas":29,"dcalc":212,"primary_image_id":11},2111,"Jolliffeite","NiAsSe",6.5,{"id":262,"name":263,"entrytype":9,"csystem":127,"ima_formula":264,"mindat_formula":264,"hmin":146,"hmax":146,"dmeas":29,"dcalc":265,"primary_image_id":11},10743,"Laflammeite","Pd\u003Csub>3\u003C\u002Fsub>Pb\u003Csub>2\u003C\u002Fsub>S\u003Csub>2\u003C\u002Fsub>","9.41",{"id":267,"name":268,"entrytype":9,"csystem":127,"ima_formula":269,"mindat_formula":269,"hmin":270,"hmax":90,"dmeas":271,"dcalc":272,"primary_image_id":273},2830,"Nagyágite","[Pb\u003Csub>3\u003C\u002Fsub>(Pb,Sb)\u003Csub>3\u003C\u002Fsub>S\u003Csub>6\u003C\u002Fsub>](Au,Te)\u003Csub>3\u003C\u002Fsub>",1,"7.35","7.29",16973,{"id":275,"name":276,"entrytype":9,"csystem":26,"ima_formula":277,"mindat_formula":277,"hmin":34,"hmax":35,"dmeas":278,"dcalc":279,"primary_image_id":280},3180,"Petzite","Ag\u003Csub>3\u003C\u002Fsub>AuTe\u003Csub>2\u003C\u002Fsub>","8.7","8.74",19202,{"id":282,"name":283,"entrytype":9,"csystem":151,"ima_formula":284,"mindat_formula":285,"hmin":286,"hmax":286,"dmeas":29,"dcalc":287,"primary_image_id":288},3920,"Tetra-auricupride","CuAu","AuCu",4.5,"14.67",2331,{"id":290,"name":291,"entrytype":9,"csystem":120,"ima_formula":292,"mindat_formula":292,"hmin":74,"hmax":74,"dmeas":29,"dcalc":293,"primary_image_id":294},4127,"Uytenbogaardtite","Ag\u003Csub>3\u003C\u002Fsub>AuS\u003Csub>2\u003C\u002Fsub>","8.40",27176,[],[],30869,[299,302,306,310,314,318,322,326,330,334,337,340,344,348,351,354,358,361,365,368,372,375,379,382,386,390,395,399,403,406,410,414,418,422,425,429,433,436,439,443,446,449,452,455,459,463,466,469,473,477,481,484,487,491,495,499,503,507,511,515],{"id":300,"year":11,"html":301,"doi":11},16110604,"[Problem of gold-bearing conglomerates].",{"id":303,"year":304,"html":305,"doi":11},16110548,1852,"Wibel (1852) Naturwissenschaftlicher Verein, Hamburg . Abhandlungen und Verhandlungen: 2: 87.",{"id":307,"year":308,"html":309,"doi":11},16110549,1895,"Hatch, F.H. and J.A. Chalmers (1895) The Gold Mines of the Rand. London: Macmillan & Co.",{"id":311,"year":312,"html":313,"doi":11},16110550,1898,"Scupham, J.R. (1898) The Buried Rivers of California as a Source of Gold. Mines and Minerals - November 1898.",{"id":315,"year":316,"html":317,"doi":11},16110551,1899,"Outerbridge Jr., Alexander E. (1899) Marvellous Increase in Production of Gold. AP Popular Science Monthly, March 1899.",{"id":319,"year":320,"html":321,"doi":11},16110552,1900,"Stone, George H. (1900) Gold Placers in Glaciated Regions. Mines and Minerals (June 1900).",{"id":323,"year":324,"html":325,"doi":11},16110553,1903,"Krusch (1903) Zeitschrift für praktische Geologie, Berlin, hale a.S.: 11: 331 (Simpson analysis).",{"id":327,"year":328,"html":329,"doi":11},16110554,1904,"Spencer, Arthur C. (1904) The Geology of the Treadwell Ore Deposits, Douglas Island, Alaska. Transaction of the American Institute of Mining Engineers - October 1904.",{"id":331,"year":332,"html":333,"doi":11},16110555,1905,"Douglass, Earl (1905) Source of the Placer Gold in Alder Gulch, Montana. Mines and Minerals - February 1905.",{"id":335,"year":332,"html":336,"doi":11},16110556,"Evans, Horace F. (1905) The Source of the Fraser River Gold. Mining World - September 2, 1905.",{"id":338,"year":332,"html":339,"doi":11},16110557,"Wilkinson, H.L. (1905) Deep Placer Deposits of Victoria. Engineering and Mining Journal - December 30, 1905.",{"id":341,"year":342,"html":343,"doi":11},16110558,1906,"Hart, T.S. (1906) Victorian Auriferous Occurrences. Australian Mining Standard - July 25, August 1, 1906. Serial. 2 parts.",{"id":345,"year":346,"html":347,"doi":11},16110559,1907,"Nenadkevwitsch (1907) Academy of Sciences, St. Petersburg, Trav. Mus. géol.: 1: 81.",{"id":349,"year":346,"html":350,"doi":11},16110560,"Gregory, John W. (1907) Gold Mining and Gold Production (Cantor Lecture). Journal of the Society of Arts - Sept. 13, 1907. Serial. 1st part.",{"id":352,"year":346,"html":353,"doi":11},16110561,"Tyrrell, J.B. (1907) Concentration of Gold in the Klondike. Economic Geology - June 1907.",{"id":355,"year":356,"html":357,"doi":11},16110562,1909,"Garrison, F. Lynwood (1909) Nature of Mining and Scientific Press - May 29, 1909.",{"id":359,"year":356,"html":360,"doi":11},16110563,"Samojloff (1909) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 46: 286.",{"id":362,"year":363,"html":364,"doi":11},16110564,1910,"Cochrane, N.D. (1910) Geological Features of Fiji. Australian Mining Standard - August 3, 1910.",{"id":366,"year":363,"html":367,"doi":11},16110565,"Day, Sosman (1910) American Journal of Science: 29: 93.",{"id":369,"year":370,"html":371,"doi":11},16110566,1911,"Lincoln, F.C. (1911) Types of Canadian Gold Deposits. Economic Geology: 6: 247.",{"id":373,"year":370,"html":374,"doi":11},16110567,"Thomas, Jr., C.S. (1911) The Bugbear of Gold. Mining and Scientific Press - May 13, 1911.",{"id":376,"year":377,"html":378,"doi":11},16110568,1912,"Chernik (1912) Imperial Academy of Sciences, St. Petersburg, Trav. Mus. géol.: 6: 78.",{"id":380,"year":377,"html":381,"doi":11},16110569,"Lakes, A. (1912) Geology of the Breckenridge Placers. Mines and Minerals - February 1912.",{"id":383,"year":384,"html":385,"doi":11},16110578,1913,"Strukturberichte (1913-1926): 504 (Au-Cu series).",{"id":387,"year":388,"html":389,"doi":11},16110570,1914,"Nenadkevwitsch (1914) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 53: 609.",{"id":391,"year":392,"html":393,"doi":394},400144,1916,"Ungemach, Henri (1916) Contribution à la Minéralogie de Madagascar. \u003Ci>Bulletin de Minéralogie\u003C\u002Fi>,  39 (1) 5-38 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.3406\u002Fbulmi.1916.3635'>doi:10.3406\u002Fbulmi.1916.3635\u003C\u002Fa>","10.3406\u002Fbulmi.1916.3635",{"id":396,"year":397,"html":398,"doi":11},16110572,1918,"Goldschmidt, V. (1918) Atlas der Krystallformen. 9 volumes, atlas, and text: Volume 4: 75.",{"id":400,"year":401,"html":402,"doi":11},16110573,1922,"Doelter, C. (1922) Handbuch der Mineral-chemie (in 4 volumes divided into parts): 3 [2]: 187.",{"id":404,"year":401,"html":405,"doi":11},16110574,"McKeehan (1922) Physical Review, a Journal of Experimental and Theoretical Physics: 20: 424.",{"id":407,"year":408,"html":409,"doi":11},16110575,1923,"Uglow, W.L., Johnston, W.A. (1923) Origin of the Placer Gold of the Barkerville Area, Cariboo District, British Columbia, Canada. Economic Geology: 18(8): 541-561.",{"id":411,"year":412,"html":413,"doi":11},16110576,1924,"Holgersson and Sedström (1924) Annalen der Physik, Halle, Leipzig: 75: 143.",{"id":415,"year":416,"html":417,"doi":11},16110577,1925,"Weiss (1925) Proceedings of the Royal Society of London: 108: 643 (artificial Au-Ag alloys).",{"id":419,"year":420,"html":421,"doi":11},16110579,1928,"Ballard, S.M. (1928) Geology and Ore Deposits of the Rocky Bar Quadrangle. Idaho Bureau of Mines and Geology - Pamphlet, no. 26, 41 pp.",{"id":423,"year":420,"html":424,"doi":11},16110584,"Strukturberichte (1928-1932): 615 (Au-Cu series).",{"id":426,"year":427,"html":428,"doi":11},16110580,1929,"Ferraz, L.C. (1929) Compendio dos Mineraes do Brazil en forma Diccionario 645pp., Rio de Janeiro: 326.",{"id":430,"year":431,"html":432,"doi":11},16110581,1931,"Freise, F.W. (1931) Transportation of Gold by Organic Underground Solutions. Economic Geology: 26, 421-431.",{"id":434,"year":431,"html":435,"doi":11},16110582,"Kellogg, A.E. (1931) Origin of Flour Gold in Black Sands. Mining Journal, Phoenix, Arizona: 14(20)(March 15th): 3-4 and 49-50.",{"id":437,"year":431,"html":438,"doi":11},16112107,"Schneiderhöhn, Hans, Ramdohr, Paul (1931) \u003Ci>Lehrbuch der Erzmikroskopie\u003C\u002Fi> Vol. 2. Borntraeger.",{"id":440,"year":441,"html":442,"doi":11},16110585,1933,"Drier, Walker (1933) Philosophical Magazine and Journal of Science: 16: 294.",{"id":444,"year":441,"html":445,"doi":11},16110586,"Holloway, H.L. (1933) Alluvial Gold. Mining Magazine: 49(2) (Aug): 82-85.",{"id":447,"year":441,"html":448,"doi":11},16110587,"Lindgren, W. (1933) Mineral Deposits. Fourth edition, 930pp. New York.",{"id":450,"year":441,"html":451,"doi":11},16110588,"Owen, Yates (1933) Philosophical Magazine and Journal of Science: 15: 472 (On spectroscopically pure gold).",{"id":453,"year":441,"html":454,"doi":11},16110589,"Treskinsky, S. (1933) Desert Placers. Mining Magazine: 49(4) (Oct 1933): 219-223 [Description of type of placer deposit occurring in Persia].",{"id":456,"year":457,"html":458,"doi":11},16110590,1934,"Vegard, Kloster (1934) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 89: 560.",{"id":460,"year":461,"html":462,"doi":11},16110591,1935,"Bürg, G. (1935) Die sekundaeren Umlagerungen und Anreicherungen des des Goldes in den Goldseifen. Zeitschrift für Praktische Geologie: 43(9) (Sept 1935): 134-139.",{"id":464,"year":461,"html":465,"doi":11},16110592,"Fisher, M.S. (1935) Origins and Composition of Alluvial Gold, With Special Reference to Morobe Goldfield, New Guinea. Institution of Mining and Metallurgy - Bulletin 365, 366, 367, 369 and 370 Feb 1935, 46 p supp plates, (discussion) Mar p. 1-27 Apr p. 23-4, June p. 31-2 and (author's reply) July p. 5-14.",{"id":467,"year":461,"html":468,"doi":11},16110593,"Heyerhoff, H.A. (1935) Do Gold Nuggets Grow or Are They Born that Way? Mining and Metallurgy: 16(no. 340, Apr 1935): 195.",{"id":470,"year":461,"html":471,"doi":472},105063,"Jurriaanse, T. (1935) The Crystal Structure of Au\u003Csub>2\u003C\u002Fsub>Bi. \u003Ci>Zeitschrift für Kristallographie\u003C\u002Fi>,  90 (1-6). 322-329 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1524\u002Fzkri.1935.90.1.322'>doi:10.1524\u002Fzkri.1935.90.1.322\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fzk\u002Fvol90\u002FZK90_322.pdf' class='refpdflink'>\u003C\u002Fa>","10.1524\u002Fzkri.1935.90.1.322",{"id":474,"year":475,"html":476,"doi":11},16110595,1936,"Fisher, M.S. (1936) Origin and Composition of Alluvial Gold, with Special Reference to Morobe Goldfield, New Guinea. Institution of Mining and Metallurgy - Bulletin 378, Mar 1936 p. 27-31.",{"id":478,"year":479,"html":480,"doi":11},16110596,1937,"Crampton, F.A. (1937) Occurrence of Gold in Stream Placers. Mining Journal (Phoenix, Arizona): 20(16): 3-4 and 33-34.",{"id":482,"year":479,"html":483,"doi":11},16110597,"Emmons, W.H. (1937) Gold Deposits of the World. New York: McGraw Hill.",{"id":485,"year":479,"html":486,"doi":11},16110598,"Van Aubel, R. (1937) Sur l'origine de l'or et des pepites alluvionnaires. Chronique des Mines Coloniales: 6(64): 238-262.",{"id":488,"year":489,"html":490,"doi":11},16110599,1944,"Palache, C., Berman, H., and Frondel, C. (1944) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Seventh edition, Volume I: 89-95.",{"id":492,"year":493,"html":494,"doi":11},16110600,1947,"Hoffman, A. (1947) Free Gold, Story of Canadian Mining Rinehart and Co. New York and Toronto, 420 p.",{"id":496,"year":497,"html":498,"doi":11},16110601,1959,"Gorbunov, E.Z. (1959) K voprosu o dal'nosti perenosa rossypnogo zolota ot korennykh istochnikov. Sovetskaya Geologiya: 2(6) (June 1959): 98-105. Transportation of gold during formation of placers].",{"id":500,"year":501,"html":502,"doi":11},16110602,1963,"Gorbunov, E.Z. (1963) Osobennosti razvitiya gidroseti i voprosy rossypnoi zolotonostnosti na Severo-Vostoke SSSR. Sovetskaya Geologiya n 4 Apr 1963 p 73-84 [Evolution features of hydrographic networks and problems of occurrence of gold, tin, and tungsten placers in northeast of the former Soviet Union].",{"id":504,"year":505,"html":506,"doi":11},16110605,1965,"Sher, S.D. (1965) O sootnoshenii masshtabov korennoi i rossypnoi zolotonosnosti v razlichnykh zolotonosnykh provintsiyakh zemnogo shara. Sovetskaya Geologiya n 3 Mar 1965 p. 3-9 [Relationship between the magnitude of primary gold deposits and gold placers in various gold-bearing provinces of the world].",{"id":508,"year":509,"html":510,"doi":11},16110606,1966,"Hammett, A.B.J. (1966) The History of Gold. Kerrville: Braswell Printing.",{"id":512,"year":513,"html":514,"doi":11},16110607,1973,"Ferguson, S.A. et al (1973) Gold Deposits of Ontario (2 volumes); Ontario Division of Mines Circular 13.",{"id":516,"year":517,"html":518,"doi":11},16110608,1979,"Boyle (1979) The geochemistry of gold and its deposits.",[520,530,540,550,560,568,577,585,594,602,611,620,629,637,644,651,657,666,674,684,693,701,709,717,724,734,742,749,755,764,772,781,788,795,802,808,816,823,829,836,842,848,856,864,871,879,887,895,901,907,913,920,926,933,940,948,956,964,971,977,986,992,998,1004,1010,1018,1025,1032,1038,1046,1053,1059,1068,1076,1083,1090,1098,1107,1114,1121,1128,1135,1142,1149,1156,1162,1169,1175,1181,1188,1195,1202,1209,1217,1223,1231,1239,1245,1252,1259,1264,1270,1276,1285,1292,1298,1307,1313,1319,1325,1331],{"id":521,"source_url":522,"license_code":523,"credit_html":524,"title":525,"description":526,"author":527,"original_width":528,"original_height":529},17156,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=578553","CC BY 2.0","Aram Dulyan (User:Aramgutang), via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=578553\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold on display.jpg","Crystalline \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNative_metal\" class=\"extiw\" title=\"w:Native metal\">native\u003C\u002Fa> \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"w:Gold\">gold\u003C\u002Fa> on display at the \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNatural_History_Museum\" class=\"extiw\" title=\"w:Natural History Museum\">Natural History Museum\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FLondon\" class=\"extiw\" title=\"w:London\">London\u003C\u002Fa>.","Aram Dulyan (User:Aramgutang)",768,1024,{"id":531,"source_url":532,"license_code":533,"credit_html":534,"title":535,"description":536,"author":537,"original_width":538,"original_height":539},17157,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10449238","CC BY-SA 3.0","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10449238\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-cat12a.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: near Bendigo, Victoria, Australia\u003C\u002Fdd>\n\u003Cdd>Size: small cabinet, 5.6 x 4.4 x 2.5 cm\n\u003Cdl>\u003Cdt>Gold\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>A very elaborate, 3-dimensional cluster of gold that shows complex and minute crystallization patterns, and is overall hackly in texture. 130 grams or approximately 4.25 troy ounces, this is a very displayable and impressive nugget that is not just the typical flat boring pancake from this famous goldfield!\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Robert M. Lavinsky",1343,1536,{"id":541,"source_url":542,"license_code":543,"credit_html":544,"title":545,"description":546,"author":547,"original_width":548,"original_height":549},17158,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=14524831","CC BY-SA 4.0","Didier Descouens, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=14524831\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Or Venezuela.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Native gold\u003C\u002Fa> \n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Mina Zapata, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSanta_Elena_de_Uair%C3%A9n\" class=\"extiw\" title=\"en:Santa Elena de Uairén\">Santa Elena de Uairen\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FBol%C3%ADvar\" class=\"extiw\" title=\"en:Bolívar\">Bolívar\u003C\u002Fa>, Venezuela\u003C\u002Fdd>\n\u003Cdd>Size: 3.46 x 3.12 x 1.79 cm.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Didier Descouens",2106,2205,{"id":551,"source_url":552,"license_code":553,"credit_html":554,"title":555,"description":556,"author":557,"original_width":558,"original_height":559},17159,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=86482577","CC BY 4.0","Marie-Lan Taÿ Pamart, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=86482577\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Native gold Auguste Goné MNHN Minéralogie.jpg","Gold nugget (229.5 g) found by Parisian Auguste Goné in California in 1851, during the gold rush. Given to the Museum by his daughter Agathe Goné in 1959. Gallery of Mineralogy and Geology of the French National Museum of Natural History in Paris.","Marie-Lan Taÿ Pamart",2800,3500,{"id":561,"source_url":562,"license_code":553,"credit_html":563,"title":564,"description":565,"author":557,"original_width":566,"original_height":567},17160,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=86726528","Marie-Lan Taÿ Pamart, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=86726528\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Native gold Louisa Creek MNHN Minéralogie.jpg","Native gold (352,5 g) from Louisa Creek, Australia. Gallery of Mineralogy and Geology of the French National Museum of Natural History in Paris.",3000,2400,{"id":569,"source_url":570,"license_code":533,"credit_html":571,"title":572,"description":573,"author":574,"original_width":575,"original_height":576},69404,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7611254","Alchemist-hp (talk) www.pse-mendelejew.de, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7611254\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-crystals.jpg","Synthetic made \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"w:Gold\">gold\u003C\u002Fa> crystals by the \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FChemical_transport_reaction\" class=\"extiw\" title=\"w:Chemical transport reaction\">chemical transport reaction\u003C\u002Fa> in chlorine gas. Purity >99.99%","Alchemist-hp (talk) www.pse-mendelejew.de",4788,3102,{"id":578,"source_url":579,"license_code":553,"credit_html":580,"title":581,"description":582,"author":557,"original_width":583,"original_height":584},17161,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=132936036","Marie-Lan Taÿ Pamart, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=132936036\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Native gold Dalmatia MNHN Minéralogie.jpg","Native gold from the Dalmatia mine, California, United States. Geology and Mineralogy Gallery of the National Museum of Natural History in Paris.",5586,4469,{"id":586,"source_url":587,"license_code":543,"credit_html":588,"title":589,"description":590,"author":591,"original_width":592,"original_height":593},17162,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=163694695","Motekov, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=163694695\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","NATIVE GOLD FROM ETROPOLE, COLL. YOVCHO YOVCHEV - EARTH AND MAN MUSEUM, SOFIA, BULGARIA.jpg","NATIVE GOLD FROM ETROPOLE, COLL. YOVCHO YOVCHEV - EARTH AND MAN MUSEUM, SOFIA, BULGARIA","Motekov",1220,788,{"id":595,"source_url":596,"license_code":553,"credit_html":597,"title":598,"description":599,"author":557,"original_width":600,"original_height":601},17163,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=182879333","Marie-Lan Taÿ Pamart, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=182879333\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Native gold Jamestown California Minéraux SU.jpg","Native gold from Jamestown, California, USA. Sorbonne University mineral collection.",4744,7116,{"id":603,"source_url":604,"license_code":523,"credit_html":605,"title":606,"description":607,"author":608,"original_width":609,"original_height":610},69408,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87884963","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87884963\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold (Rose Creek, near Winnemucca, Nevada, USA) 5.jpg","Native gold from Nevada, USA. (3.7 ounces)\n\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 5500 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Gold (Au) is the most prestigious metal known (but not the most valuable).  Gold is the only metal that has a deep, rich, metallic yellow color.  Almost all other metals are silvery-colored.\n\u003C\u002Fp>\u003Cp>Gold is very rare in crustal rocks - it averages about 4 ppb (parts per billion).  Where gold has been concentrated, it occurs as wires, dendritic crystals, twisted sheets, octahedral crystals, and variably-shaped nuggets.  It most commonly occurs in hydrothermal quartz veins, disseminated in some contact- & hydrothermal-metamorphic rocks, and in placer deposits.  Placers are concentrations of heavy minerals in stream gravels or in cracks on bedrock-floored streams.  Gold has a high specific gravity (about 19), so it easily accumulates in placer deposits.  Its high density allows prospectors to readily collect placer gold by panning.\n\u003C\u002Fp>\u003Cp>In addition to its high density, gold has a high melting point (over 1000º C).  Gold is also relatively soft - about 2.5 to 3 on the Mohs Hardness Scale.  The use of pure gold or high-percentage gold in jewelry is not desirable as it easily gets scratched.  The addition of other metals to gold to increase the hardness also alters the unique color of gold.  Gold jewelry made & sold in America doesn’t have the gorgeous rich color of high-purity gold.\n\u003C\u002Fp>\u003Cp>Locality: Rose Creek, near WInnemucca, northern Nevada, USA\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of gold:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=1720","James St. John",1866,1198,{"id":612,"source_url":613,"license_code":543,"credit_html":614,"title":615,"description":616,"author":617,"original_width":618,"original_height":619},69412,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=123029636","Filip Kubálek, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=123029636\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Zlato.jpg","Zlato v křemeni","Filip Kubálek",4624,2604,{"id":621,"source_url":622,"license_code":553,"credit_html":623,"title":624,"description":625,"author":626,"original_width":627,"original_height":628},69418,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=174694394","Hypsibius, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=174694394\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Or natif MNHN.jpg","Or natif. Mine Dalmatia, Californie, Etats-Unie. Ancienne collection et legs Vésigné, 1955. Exposé dans la galerie de minérologie du Muséum national d'histoire naturelle, à Paris","Hypsibius",4096,3072,{"id":630,"source_url":631,"license_code":533,"credit_html":632,"title":633,"description":634,"author":537,"original_width":635,"original_height":636},9986,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10119875","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10119875\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-20411.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Östra Hardmalmen Orebody, Falun Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FFalun\" class=\"extiw\" title=\"en:Falun\">Falun\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FDalarna\" class=\"extiw\" title=\"en:Dalarna\">Dalarna\u003C\u002Fa>, Sweden (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-207636.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 6.0 x 5.6 x 5.0 cm.\u003C\u002Fdd>\n\u003Cdd>A very rarely seen historic Gold specimen from Sweden of all places. This specimen came to Richard Kosnar from noted Swedish collector, Stig Adolfsson in October of 1985. It features on notable sharp octahedral crystal of Gold along with crystalline Gold sitting in quartzite rock, and according to the label, is associated with the rare bismuth, selenium sulfide Pekoite and the rare lead copper bismuth sulfide Gladite plus minor Chalcopyrite. Stig’s original label comes attached to the box with this piece, (along with Richard Kosnar’s typed number attached to the back of the specimen) and as you can see the label states that this is the only known locality for crystallized gold in Sweden.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",413,360,{"id":638,"source_url":639,"license_code":533,"credit_html":640,"title":641,"description":634,"author":537,"original_width":642,"original_height":643},9987,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10166007","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10166007\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-244205.jpg",487,432,{"id":645,"source_url":646,"license_code":533,"credit_html":647,"title":648,"description":649,"author":537,"original_width":650,"original_height":643},13857,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10165215","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10165215\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-239889.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Östra Hardmalmen Orebody, Falun Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FFalun\" class=\"extiw\" title=\"en:Falun\">Falun\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FDalarna\" class=\"extiw\" title=\"en:Dalarna\">Dalarna\u003C\u002Fa>, Sweden (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-207636.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 6.0 x 5.6 x 5.0 cm.\u003C\u002Fdd>\n\u003Cdd>A very rarely seen historic Gold specimen from Sweden. This specimen came to Rich Kosnar from noted Swedish collector, Stig Adolfsson in February of 1985. It features small patches of crystalline Gold sitting in quartzite rock, and according to the label, is associated with the rare bismuth, selenium sulfides \"Laitakarite and probably Weibullite\". Stig's original label comes attached to the box with this piece, (along with Rich Kosnar's typed number attached to the back of the specimen) and his information states that this piece is nearly a century old.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",510,{"id":652,"source_url":653,"license_code":533,"credit_html":654,"title":655,"description":649,"author":537,"original_width":656,"original_height":636},13858,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10165216","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10165216\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-239890.jpg",383,{"id":658,"source_url":659,"license_code":543,"credit_html":660,"title":661,"description":662,"author":663,"original_width":664,"original_height":665},24308,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=180411693","Марися Лебідь, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=180411693\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Золото-сульфідна руда пошарово-вкрапленої руди.jpg","Minerals in Yevhen Lazarenko Mineralogical Museum","Марися Лебідь",4080,3060,{"id":667,"source_url":668,"license_code":523,"credit_html":669,"title":670,"description":671,"author":608,"original_width":672,"original_height":673},55860,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34370241","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34370241\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Larder Lake mine Gold Ore, Ontario, Canada.jpg","\u003Cp>Larder Lake Gold Ore (2.1 cm across) with auriferous quartz hydrothermal vein in Archean-aged, fuchsite-rich metamorphic rock.  Fuchsite is a greenish, chromian mica.\n\u003C\u002Fp>\u003Cp>Locality: Chesterville Mine, Larder Lake Mining District, Ontario, Canada.\n\u003C\u002Fp>\nSpecimen owned by Ohio State University's Geology Department (Columbus, Ohio, USA).",1978,1858,{"id":675,"source_url":676,"license_code":677,"credit_html":678,"title":679,"description":680,"author":681,"original_width":682,"original_height":683},60701,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=17885995","Public domain","Parent Géry, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=17885995\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaze impériale (Mine de Vermelhão, Saramenha, Ouro Preto, Minas Gerais - Brésil) 2.jpg","topaz var. imperial topaz : Vermelhão Mine, Saramenha, Ouro Preto, Mucury Valley, Minas Gerais, Brazil","Parent Géry",2415,3979,{"id":685,"source_url":686,"license_code":677,"credit_html":687,"title":688,"description":689,"author":690,"original_width":691,"original_height":692},67037,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=120445617","Jim Bell and the Panoramic Camera (PanCam) Team of the NASA Mer Opportunity, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=120445617\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sol287B.294.Burns Cliff.jpg","IDL TIFF file","Jim Bell and the Panoramic Camera (PanCam) Team of the NASA Mer Opportunity",12316,4218,{"id":694,"source_url":695,"license_code":523,"credit_html":696,"title":697,"description":698,"author":608,"original_width":699,"original_height":700},67509,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34406927","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34406927\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Homestake Mine gold ore closeup.jpg","\u003Cp>Homestake Mine gold ore (~3.5 cm across) - numerous visible gold blebs in high-grade gold ore sample from the Homestake Mine, town of Lead, northern Black Hills, western South Dakota, USA.\n\u003C\u002Fp>\u003Cp>The largest gold mine in the Americas was the long-lived Homestake Mine in the town of Lead (pronounced “Leed”), South Dakota, USA.  Located in the Lead Window of the northern Black Hills Uplift in western South Dakota, the Homestake Mine produced about 40 million ounces of gold.  The gold at Homestake is almost exclusively confined to the Homestake Formation, a Paleoproterozoic (~1.9-2.0 billion years) sedimentary unit that originally consisted of interbedded Mg-rich siderite iron formation and marlstones.\n\u003C\u002Fp>\nThe Homestake Formation has been strongly deformed & multiply metamorphosed, and many of the original rocks were converted to greenschists (cummingtonite schists).  The gold has been interpreted as having been originally deposited with the iron formation sediments by seafloor volcanogenic exahalative processes.  Slight metamorphic gold mobilization and tight structural folding has resulted in the formation of auriferous greenschist pods along fold axes.",785,690,{"id":702,"source_url":703,"license_code":523,"credit_html":704,"title":705,"description":706,"author":608,"original_width":707,"original_height":708},73589,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=83657189","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=83657189\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Roasted Cripple Creek gold ore (Cripple Creek Diatreme, Early Oligocene, 32 Ma; Cripple Creek, Colorado, USA) 4 (17199488901).jpg","\u003Cp>Roasted gold ore from Cripple Creek, Colorado, USA. (public display, Montana Bureau of Mines and Geology Mineral Museum, Butte, Montana, USA)  Artificial heating has driven tellurium (Te) away from the original telluride minerals (for example, calaverite), leaving behind vesicular blebs of gold.\n\u003C\u002Fp>\u003Cp>The Cripple Creek Gold District of central Colorado, USA is famous for its unusual gold and silver mineralization.  Precious metal mineralization occurs in the Cripple Creek Diatreme, the root zone of a deeply eroded volcano dating to the Early Oligocene (32 Ma).\n\u003C\u002Fp>\u003Cp>The dominant lithology at Cripple Creek is the scarce igneous rock phonolite, an alkaline, intermediate, extrusive igneous rock.  Cripple Creek gold can be found in its native state (Au), but it typically occurs in the form of gold telluride minerals: sylvanite ((Au,Ag)2Te4), calaverite (AuTe2), petzite (Ag3AuTe2), krennerite ((Au,Ag)Te2), and nagyagite (Pb5Au(Sb,Bi)Te2S6).  Silver also occurs in some Cripple Creek minerals, including sylvanite, petzite, krennerite, hessite (Ag2Te), tennantite ((Cu,Ag,Fe,Zn)12As4S13), acanthite (Ag2S), and tetrahedrite ((Cu,Fe,Ag,Zn)12Sb4S13).\n\u003C\u002Fp>\nThe gold telluride minerals common in the Cripple Creek Diatreme lack the wonderful, deep rich yellow color of native gold.  Some Cripple Creek rock samples have been artificially “roasted” to drive off the tellurium.  With heat, the Te readily volatilizes, leaving behind relatively pure gold.  The gold patches on the rock below are surficial blisters and crusts of gold having a fine-scale vesicular texture (lots of tiny holes, like a pumice or scoria).",1732,1108,{"id":710,"source_url":711,"license_code":523,"credit_html":712,"title":713,"description":714,"author":608,"original_width":715,"original_height":716},82292,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=124841135","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=124841135\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Roasted gold ore (Cripple Creek Diatreme, Early Oligocene, 32 Ma; Cripple Creek, Colorado, USA) 5.jpg","Roasted gold ore from Cripple Creek, Colorado, USA. (~7.2 centimeters across at its widest)\n\u003Cp>The Cripple Creek Gold District of central Colorado is famous for its unusual gold and silver mineralization.  Precious metal mineralization occurs in the Cripple Creek Diatreme, the root zone of a deeply eroded volcano of Early Oligocene age (32 million years old).\n\u003C\u002Fp>\u003Cp>The dominant lithology at Cripple Creek is phonolite, a scarce, alkaline, intermediate, extrusive igneous rock.  Cripple Creek gold can be found in its native state (Au), but it typically occurs in the form of gold telluride minerals such as sylvanite ((Au,Ag)2Te4), calaverite (AuTe2), petzite (Ag3AuTe2), krennerite ((Au,Ag)Te2), and nagyagite (Pb5Au(Sb,Bi)Te2S6).  Silver also occurs in some Cripple Creek minerals, including sylvanite, petzite, krennerite, hessite (Ag2Te), tennantite ((Cu,Ag,Fe,Zn)12As4S13), acanthite (Ag2S), and tetrahedrite ((Cu,Fe,Ag,Zn)12Sb4S13).\n\u003C\u002Fp>\nThe gold telluride minerals common in the Cripple Creek Diatreme lack the wonderful, deep rich yellow color of native gold.  Some Cripple Creek rock samples have been artificially “roasted” to drive off the tellurium.  With heat, the Te readily volatilizes, leaving behind relatively pure gold.  The gold patches on the rock seen here are surficial blisters and crusts of gold.",3816,2993,{"id":718,"source_url":719,"license_code":533,"credit_html":720,"title":721,"description":722,"author":537,"original_width":723,"original_height":643},8759,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10169341","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10169341\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Bustamite-Ferrobustamite-261601.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FBustamite\" class=\"extiw\" title=\"en:Bustamite\">Bustamite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FFerrobustamite\" class=\"extiw\" title=\"en:Ferrobustamite\">Ferrobustamite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FIdarado_Mine\" class=\"extiw\" title=\"en:Idarado Mine\">Idarado Mine\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTelluride\" class=\"extiw\" title=\"en:Telluride\">Telluride\u003C\u002Fa>, Ouray District (Uncompahgre District), San Miguel County, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FColorado\" class=\"extiw\" title=\"en:Colorado\">Colorado\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-3660.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 7.6 x 5.7 x 2.2 cm.\u003C\u002Fdd>\n\u003Cdd>A very rare polished specimen of classic \"Dust Gold\" associated with pinkish-brown Bustamite and Ferrobustamite set into massive white Quartz from the Idarado mine near Telluride. This specimen was analyzed by the late great mineralogist Gene Foord back in the early 1980s, and remains one of the only specimens of Bustamite\u002FFerrobustamite that I have seen from this mine. Ex. Richard Kosnar Collection.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",498,{"id":725,"source_url":726,"license_code":727,"credit_html":728,"title":729,"description":730,"author":731,"original_width":732,"original_height":733},19467,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196493","CC BY-SA 2.0","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196493\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Wehrlite with Arsenopyrite and Gold (46873081262).jpg","\u003Cp>Soverign-Telluride-Gold Property Mine\nJones Creek, Hope\nBritish Columbia, Canada\n\u003C\u002Fp>\nS-74-171","Pacific Museum of Earth from Canada",4000,6000,{"id":735,"source_url":736,"license_code":543,"credit_html":737,"title":738,"description":739,"author":740,"original_width":741,"original_height":741},69402,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=2460665","Raimond Spekking, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=2460665\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Naturkundemuseum Berlin - Gediegen Gold in Quarz, Eagles Nest Mine, Placer County, Kalifornien, USA.jpg","Native gold in quarz - Eagles Nest Mine, Placer County, California, USA.  To make the gold crystals visible, the quartz was partially etched away. \u003Ca href=\"\u002F\u002Fcommons.wikimedia.org\u002Fwiki\u002FMuseum_f%C3%BCr_Naturkunde_(Berlin)\" title=\"Museum für Naturkunde (Berlin)\">Museum für Naturkunde (Berlin)\u003C\u002Fa>.","Raimond Spekking",1000,{"id":743,"source_url":744,"license_code":543,"credit_html":745,"title":746,"description":739,"author":740,"original_width":747,"original_height":748},69403,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=4046401","Raimond Spekking, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=4046401\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Naturkundemuseum Berlin - Gediegen Gold in Quarz, Eagles Nest Mine, Placer County, Kalifornien, USA, lower resolution.JPG",835,425,{"id":750,"source_url":751,"license_code":543,"credit_html":752,"title":753,"description":754,"author":617,"original_width":618,"original_height":619},69411,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=123029634","Filip Kubálek, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=123029634\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold in quartz.jpg","Gold in quartz",{"id":756,"source_url":757,"license_code":543,"credit_html":758,"title":759,"description":760,"author":761,"original_width":762,"original_height":763},69413,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=132781300","Eric Polk, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=132781300\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold with arsenopyrite.png","Sample of Gold with arsenopyrite collected from Sierra County, California, USA. On display at the Natural History Museum of Los Angeles County, Los Angeles, California, USA.","Eric Polk",1496,1602,{"id":765,"source_url":766,"license_code":533,"credit_html":767,"title":768,"description":769,"author":537,"original_width":770,"original_height":771},2316,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10444435","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10444435\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Aurichalcite-Calcite-aur13d.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAurichalcite\" class=\"extiw\" title=\"en:Aurichalcite\">Aurichalcite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCalcite\" class=\"extiw\" title=\"en:Calcite\">Calcite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Ojuela Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMapim%C3%AD\" class=\"extiw\" title=\"en:Mapimí\">Mapimí\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMapim%C3%AD_(municipality)\" class=\"extiw\" title=\"en:Mapimí (municipality)\">Municipio de Mapimí\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FDurango\" class=\"extiw\" title=\"en:Durango\">Durango\u003C\u002Fa>, Mexico (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-2318.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: miniature, 4.3 x 2.7 x 1.8 cm\n\u003Cdl>\u003Cdt>Aurichalcite in Calcite\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>Sitting high on a limonite matrix are tabular rhombs of glassy and translucent, calcite, to 1.2 cm across. These rhombs have been heavily include by fibrous aurichalcite resulting in a beautiful, rich teal coloration. Very aesthetic!\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",1682,1358,{"id":773,"source_url":774,"license_code":543,"credit_html":775,"title":776,"description":777,"author":778,"original_width":779,"original_height":780},4334,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146905118","Kritzolina, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146905118\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Coloradoite, Calaverite and Gold 01.jpg","Coloradoite, calaverite and gold from Kalgoorlie, Australia","Kritzolina",4147,2765,{"id":782,"source_url":783,"license_code":543,"credit_html":784,"title":785,"description":777,"author":778,"original_width":786,"original_height":787},4335,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146905119","Kritzolina, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146905119\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Coloradoite, Calaverite and Gold 02.jpg",4890,3260,{"id":789,"source_url":790,"license_code":543,"credit_html":791,"title":792,"description":777,"author":778,"original_width":793,"original_height":794},4336,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146905120","Kritzolina, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146905120\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Coloradoite, Calaverite and Gold 03.jpg",4436,2958,{"id":796,"source_url":797,"license_code":533,"credit_html":798,"title":799,"description":800,"author":537,"original_width":801,"original_height":643},4854,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10162303","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10162303\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Quartz-221291.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FQuartz\" class=\"extiw\" title=\"en:Quartz\">Quartz\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Gold Lake Mine, Little Giant Basin, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSilverton\" class=\"extiw\" title=\"en:Silverton\">Silverton\u003C\u002Fa>, Silverton District, San Juan County, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FColorado\" class=\"extiw\" title=\"en:Colorado\">Colorado\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-204313.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 7.5 x 5.0 x 3.1 cm.\u003C\u002Fdd>\n\u003Cdd>A lovely crystal group of cathedral Quartz prisms with very pale Amethyst (\"Amethystine\") tapered terminations from the Gold Lake mine. It is an aesthetic specimen with attractive crystals that are water clear at the tips. Ex. Jaime Bird Collection.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",514,{"id":803,"source_url":804,"license_code":533,"credit_html":805,"title":806,"description":800,"author":537,"original_width":807,"original_height":636},4855,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10162304","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10162304\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Quartz-221292.jpg",405,{"id":809,"source_url":810,"license_code":533,"credit_html":811,"title":812,"description":813,"author":814,"original_width":529,"original_height":815},5197,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=12388127","Joachim Esche, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=12388127\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Chalcophanite - Gold Hill Mine, Deep Creek Mts, Utah, USA.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FChalcophanite\" class=\"extiw\" title=\"en:Chalcophanite\">Chalcophanite\u003C\u002Fa> (image width: 4 mm)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: 80(-foot) level, Gold Hill Mine (Western Utah Mine), Gold Hill, Gold Hill District (Clifton District), Deep Creek Mts, Tooele Co., Utah, USA\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Joachim Esche",651,{"id":817,"source_url":818,"license_code":543,"credit_html":819,"title":820,"description":821,"author":740,"original_width":822,"original_height":822},6145,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=2460264","Raimond Spekking, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=2460264\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Naturkundemuseum Berlin - Konichalcit - Gold Hill, Utah, USA.jpg","Konichalcit, Gold Hill, Tooele Co., Utah, USA. \u003Ca href=\"\u002F\u002Fcommons.wikimedia.org\u002Fwiki\u002FMuseum_f%C3%BCr_Naturkunde_(Berlin)\" title=\"Museum für Naturkunde (Berlin)\">Museum für Naturkunde (Berlin)\u003C\u002Fa>.",1600,{"id":824,"source_url":825,"license_code":533,"credit_html":826,"title":827,"description":722,"author":537,"original_width":828,"original_height":636},8760,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10169342","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10169342\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Bustamite-Ferrobustamite-261602.jpg",457,{"id":830,"source_url":831,"license_code":543,"credit_html":832,"title":833,"description":834,"author":835,"original_width":628,"original_height":664},9513,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=155612347","Hans Knöfler, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=155612347\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gadolinit-\"Sonne\", Vang Granitbrud, Bornholm.jpg","Gadolinit-\"Sonne\" in einem Pegmatitgang im Vang-Granit, Vang Granitbrud, Bornholm (Foto vom September 2024)","Hans Knöfler",{"id":837,"source_url":838,"license_code":727,"credit_html":839,"title":840,"description":841,"author":731,"original_width":733,"original_height":732},9592,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118205539","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118205539\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Galenobismutite with Cosalite and Gold (46995644805).jpg","\u003Cp>Wells\nBritish Columbia, Canada\n\u003C\u002Fp>\nS-74-2021",{"id":843,"source_url":844,"license_code":727,"credit_html":845,"title":846,"description":847,"author":731,"original_width":732,"original_height":733},9595,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118206756","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118206756\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Pyrite with Cosalite, Gold, and Galenobismutite (47859659382).jpg","\u003Cp>Wells\nBritish Columbia, Canada\n\u003C\u002Fp>\nS-74-1672",{"id":849,"source_url":850,"license_code":533,"credit_html":851,"title":852,"description":853,"author":537,"original_width":854,"original_height":855},10140,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10140823","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10140823\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-121980.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 3.7 x 1.8 x 1.1 cm.\u003C\u002Fdd>\n\u003Cdd>A superb and sizeable gem crystal of the prized \"imperial\" topaz from the locality famous for these golden crystals. This crystal is complete all around and undamaged, with a sharp, perfect termination. It has super luster. The golden\u002Famber color is so intense that in some lights the crystal actually has a pink\u002Fred overtone to it. This fine crystal weighs 15 grams.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",347,600,{"id":857,"source_url":858,"license_code":533,"credit_html":859,"title":860,"description":861,"author":537,"original_width":862,"original_height":863},10141,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10141013","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10141013\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-122807.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 6.2 x 1.1 x 0.8 cm.\u003C\u002Fdd>\n\u003Cdd>GORGEOUS, gemmy and lustrous, golden amber, imperial topaz crystal from Ouro Preto. This is definitely a Holy Grail species for the topaz or Brazilian pegmatite collector and this is a beauty. The classic chisel termination highlights this fine crystal, which has excellent clarity and gemminess. It is very nearly pristine, with only very minor contacting near the base. 11 grams.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",153,449,{"id":865,"source_url":866,"license_code":533,"credit_html":867,"title":868,"description":861,"author":537,"original_width":869,"original_height":870},10142,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10141014","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10141014\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-122808.jpg",261,350,{"id":872,"source_url":873,"license_code":533,"credit_html":874,"title":875,"description":876,"author":537,"original_width":877,"original_height":878},10143,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10151017","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10151017\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-174593.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 2.9 x 1.1 x 0.6 cm.\u003C\u002Fdd>\n\u003Cdd>Golden imperial topaz from Ouro Preto, Brazil. This gemmy and striated crystal has excellent lustre, color and fire. 3.75 grams or 18.76 carats.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",220,399,{"id":880,"source_url":881,"license_code":533,"credit_html":882,"title":883,"description":884,"author":537,"original_width":885,"original_height":886},11236,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10453007","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10453007\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Hessite-mf11b.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FHessite\" class=\"extiw\" title=\"en:Hessite\">Hessite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Botés, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAlba_County\" class=\"extiw\" title=\"en:Alba County\">Alba County\u003C\u002Fa>, Romania (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-24510.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: thumbnail, 2.1 x 1.7 x 1.5 cm\n\u003Cdl>\u003Cdt>Hessite, Gold\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>WOW! This is an incredible, world-class thumbnail of this very rare silver species! Such pieces are usually 100-200 years old and more. Pristine, aesthetic examples are few and far between in any size, but THIS ONE is a competition level piece for aesthetics, aside from the rarity and history. Note the Smithsonian label showing it is from the Carl Bosch collection. Bosch didn't collect anything bad. Even his small stuff is good, as this exemplifies!\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",694,780,{"id":888,"source_url":889,"license_code":677,"credit_html":890,"title":891,"description":892,"author":893,"original_width":894,"original_height":894},12556,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1955940","Dave Dyet http:\u002F\u002Fwww.shutterstone.com http:\u002F\u002Fwww.dyet.com, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1955940\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Austinite on limonite w - adamite Basic zinc calcium arsenate Gold Hill Tooele County Utah 2355.jpg","These mineral images are free to use how you wish.","Dave Dyet http:\u002F\u002Fwww.shutterstone.com http:\u002F\u002Fwww.dyet.com",700,{"id":896,"source_url":897,"license_code":727,"credit_html":898,"title":899,"description":900,"author":731,"original_width":732,"original_height":733},12703,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118205036","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118205036\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Bismuthinite and Joséite with Gold (33876000098).jpg","\u003Cp>Glacier Gulch\nHudson Bay Mountain, Smithers\nBritish Columbia, Canada\n\u003C\u002Fp>\n\u003Col>\u003Cli>600\u003C\u002Fli>\u003C\u002Fol>",{"id":902,"source_url":903,"license_code":727,"credit_html":904,"title":905,"description":906,"author":731,"original_width":732,"original_height":733},15221,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118204964","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118204964\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Bismuthinite with Bismuth, Gold, Arsenopyrite, Marcasite, Quartz, and Cassiterite (33876006478).jpg","\u003Cp>Marcamarami Mine\nSorata, La Paz\nBolivia\n\u003C\u002Fp>\n\u003Col>\u003Cli>609\u003C\u002Fli>\u003C\u002Fol>",{"id":908,"source_url":909,"license_code":533,"credit_html":910,"title":911,"description":912,"author":537,"original_width":855,"original_height":189},16433,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10175843","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10175843\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Mohawkite-121691.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMohawkite\" class=\"extiw\" title=\"en:Mohawkite\">Mohawkite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAhmeek,_Michigan\" class=\"extiw\" title=\"en:Ahmeek, Michigan\">Ahmeek\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FKeweenaw_County,_Michigan\" class=\"extiw\" title=\"en:Keweenaw County, Michigan\">Keweenaw County\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMichigan\" class=\"extiw\" title=\"en:Michigan\">Michigan\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-24712.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 4.8 x 3.7 x 1.3 cm.\u003C\u002Fdd>\n\u003Cdd>\"Mohawkite\", a rare mixture of copper and copper arsenides, is named after the Mohawk-Ahmeek area of Keweenaw County in Michigan. This 2.9-ounce nugget has been polished to show its pretty silvery tone with a hint of gold. Mined in the 1950s.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",{"id":914,"source_url":915,"license_code":533,"credit_html":916,"title":917,"description":918,"author":537,"original_width":855,"original_height":919},16435,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10176750","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10176750\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Mohawkite-210766.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMohawkite\" class=\"extiw\" title=\"en:Mohawkite\">Mohawkite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Mohawk Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMohawk\" class=\"extiw\" title=\"en:Mohawk\">Mohawk\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FKeweenaw_County,_Michigan\" class=\"extiw\" title=\"en:Keweenaw County, Michigan\">Keweenaw County\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMichigan\" class=\"extiw\" title=\"en:Michigan\">Michigan\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-3851.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 4.9 x 2.8 x 2.0 cm.\u003C\u002Fdd>\n\u003Cdd>Mohawkite, a rare compound of copper and arsenic, is found only one place in the world - in the Mohawk-Ahmeek area of Keweenaw County in Michigan. This 3-ounce nugget has been polished to show its pretty silvery tone with a hint of gold. From an old stash, which was mined in the 1950s. It had been sitting in a garage for a long, long time.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",400,{"id":921,"source_url":922,"license_code":727,"credit_html":923,"title":924,"description":925,"author":731,"original_width":733,"original_height":732},19463,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118188965","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118188965\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Wehrlite with Gold and Quartz (48417916382).jpg","\u003Cp>White Elephant Mine - Kelowna\nBritish Columbia, Canada\n\u003C\u002Fp>\nSpecial Features: Single Crystal",{"id":927,"source_url":928,"license_code":523,"credit_html":929,"title":930,"description":931,"author":608,"original_width":932,"original_height":708},21130,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952279","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952279\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold & roscoelite (Stuckslacker Mine, Coloma, California, USA) (16562912783).jpg","\u003Cp>Gold and roscoelite from California, USA. (public display, Leadville Mining Museum, Leadville, Colorado, USA)\n\u003C\u002Fp>\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substrance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Gold (Au) is the most prestigious metal known, but it's not the most valuable.  Gold is the only metal that has a deep, rich, metallic yellow color.  Almost all other metals are silvery-colored.  Gold is very rare in crustal rocks - it averages about 5 ppb (parts per billion).  Where gold has been concentrated, it occurs as wires, dendritic crystals, twisted sheets, octahedral crystals, and variably-shaped nuggets.  It most commonly occurs in hydrothermal quartz veins, disseminated in some contact- & hydrothermal-metamorphic rocks, and in placer deposits.  Placers are concentrations of heavy minerals in stream gravels or in cracks on bedrock-floored streams.  Gold has a high specific gravity (about 19), so it easily accumulates in placer deposits.  Its high density allows prospectors to readily collect placer gold by panning.\n\u003C\u002Fp>\u003Cp>In addition to its high density, gold has a high melting point (over 1000º C).  Gold is also relatively soft - about 2.5 to 3 on the Mohs Hardness Scale.  The use of pure gold or high-purity gold in jewelry is not desirable as it easily gets scratched.  The addition of other metals to gold to increase the hardness also alters the unique color of gold.  Gold jewelry made & sold in America doesn’t have the gorgeous rich color of high-purity gold.\n\u003C\u002Fp>\nLocality: Stuckslacker Mine, Coloma, California, USA",1797,{"id":934,"source_url":935,"license_code":523,"credit_html":936,"title":937,"description":938,"author":608,"original_width":165,"original_height":939},21131,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87884948","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87884948\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold & roscoelite (Stuckslacker Mine, Coloma, California, USA).jpg","Gold and roscoelite from California, USA. (public display, Leadville Mining Museum, Leadville, Colorado, USA)\n\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Gold (Au) is the most prestigious metal known, but it's not the most valuable.  Gold is the only metal that has a deep, rich, metallic yellow color.  Almost all other metals are silvery-colored.  Gold is very rare in crustal rocks - it averages about 5 ppb (parts per billion).  Where gold has been concentrated, it occurs as wires, dendritic crystals, twisted sheets, octahedral crystals, and variably-shaped nuggets.  It most commonly occurs in hydrothermal quartz veins, disseminated in some contact- & hydrothermal-metamorphic rocks, and in placer deposits.  Placers are concentrations of heavy minerals in stream gravels or in cracks on bedrock-floored streams.  Gold has a high specific gravity (about 19), so it easily accumulates in placer deposits.  Its high density allows prospectors to readily collect placer gold by panning.\n\u003C\u002Fp>\u003Cp>In addition to its high density, gold has a high melting point (over 1000º C).  Gold is also relatively soft - about 2.5 to 3 on the Mohs Hardness Scale.  The use of pure gold or high-purity gold in jewelry is not desirable as it easily gets scratched.  The addition of other metals to gold to increase the hardness also alters the unique color of gold.  Gold jewelry made & sold in America doesn’t have the gorgeous rich color of high-purity gold.\n\u003C\u002Fp>\u003Cp>Locality: Stuckslacker Mine, Coloma, California, USA\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of gold:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=1720",1126,{"id":941,"source_url":942,"license_code":523,"credit_html":943,"title":944,"description":945,"author":608,"original_width":946,"original_height":947},25043,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=83657467","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=83657467\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Tellurium-quartz-pyrite hydrothermal vein (Emperor Gold-Silver Telluride Deposit, Mba Volcanics, Miocene; Emperor Mine, Viti Levu, Fiji Islands) (17333016059).jpg","\u003Cp>Tellurium-quartz-pyrite hydrothermal vein from the Miocene of the Fiji Islands. (field of view 2.7 cm across)\n\u003C\u002Fp>\u003Cp>Silvery-colored = tellurium\nWhitish-gray = quartz\nBrassy gold = pyrite\nDark material at right = host rock (altered porphyritic shoshonite)\n\u003C\u002Fp>\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.\n\u003C\u002Fp>\u003Cp>Tellurium (Te) is a semimetal\u002Fmetalloid that can occur in its native state as a mineral.  It has a metallic luster, a bright silvery color, a grayish streak, is rather soft (H = 2 to 2.5), and is heavy for its size.  It is not malleable.  Tellurium can break along several cleavage planes.\n\u003C\u002Fp>\u003Cp>Tellurium is best known from precious metal telluride deposits, such as the Cripple Creek Mining District of Colorado, USA.  In such deposits, Te is usually mixed with various metals and semimetals (e.g., Au, Ag, Pb, Ni, Fe, Bi, Sb).\n\u003C\u002Fp>\u003Cp>The sample shown above is a tellurium-quartz-pyrite hydrothermal vein that is hosted in altered porphyritic shoshonite lava (see rock matrix at right).\n\u003C\u002Fp>\u003Cp>Deposit & age: Emperor Gold-Silver Telluride Deposit, Mba Volcanics, Miocene\n\u003C\u002Fp>\nLocality: Emperor Mine, near Vatukoula, Tavua Gold Field, northern Viti Levu, western Fiji Islands, southwest-central Pacific Basin (17º 30’ 24” South, 177º 51’ 12” East)",2128,1639,{"id":949,"source_url":950,"license_code":523,"credit_html":951,"title":952,"description":953,"author":608,"original_width":954,"original_height":955},25200,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952231","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952231\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-quartz-sulfide hydrothermal vein (O'Dea Vein or Irishman Vein, Late Cretaceous; Grant Mine, Fairbanks Mining District, Alaska, USA) 4 (17153075755).jpg","Gold-quartz-sulfide hydrothermal vein from the Cretaceous of Alaska, USA. (cut & polished slab; public display, Leadville Mining Museum, Leadville, Colorado, USA)\n\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substrance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Gold (Au) is the most prestigious metal known, but it's not the most valuable.  Gold is the only metal that has a deep, rich, metallic yellow color.  Almost all other metals are silvery-colored.  Gold is very rare in crustal rocks - it averages about 5 ppb (parts per billion).  Where gold has been concentrated, it occurs as wires, dendritic crystals, twisted sheets, octahedral crystals, and variably-shaped nuggets.  It most commonly occurs in hydrothermal quartz veins, disseminated in some contact- & hydrothermal-metamorphic rocks, and in placer deposits.  Placers are concentrations of heavy minerals in stream gravels or in cracks on bedrock-floored streams.  Gold has a high specific gravity (about 19), so it easily accumulates in placer deposits.  Its high density allows prospectors to readily collect placer gold by panning.\n\u003C\u002Fp>\u003Cp>In addition to its high density, gold has a high melting point (over 1000º C).  Gold is also relatively soft - about 2.5 to 3 on the Mohs Hardness Scale.  The use of pure gold or high-purity gold in jewelry is not desirable as it easily gets scratched.  The addition of other metals to gold to increase the hardness also alters the unique color of gold.  Gold jewelry made & sold in America doesn’t have the gorgeous rich color of high-purity gold.\n\u003C\u002Fp>\u003Cp>The sample shown above is hydrothermal vein rock from the Grant Mine, northwest of the city of Fairbanks, Alaska.  The mine produced gold, silver, antimony, lead, and tungsten.  Two hydrothermal veins were the principal targets of mining at this locality - the O’Dea Vein and the Irishman Vein.  This specimen may be from the O’Dea Vein, which varies in width from 6 inches to over 6 feet.  Both veins are developed in fault zones in Fairbanks Schist host rocks of probable Proterozoic age.  The rock is dominated by whitish quartz (this has been described as a “quartz breccia”), which has been mostly stained pale yellowish to reddish-brown by iron oxide.  Native gold occurs throughout the rock, plus a gray to dark gray sulfide mineral.  Minerals reported from the O’Dea Vein include quartz (SiO2 - silicon dioxide), gold (Au), arsenopyrite (FeAsS - iron arsenic sulfide), galena (PbS - lead sulfide), pyrite (FeS2 - iron sulfide), stibnite (Sb2S3 - antimony sulfide), muscovite mica (KAl2(AlSi3O10)(OH)2 - potassium hydroxy-aluminosilicate), goethite (FeO(OH) - iron hydroxy-oxide), and scheelite (CaWO4 - calcium tungstate).  The O’Dea Vein also includes fragments of Fairbanks Schist host rock and fault mylonite.  Isotopic dates on vein-fault minerals from the nearby Ryan Lode Mine, which is probably developed on the same fault zone as the Grant Mine, are 88 to 89 Ma (Late Cretaceous).  Dates from other mines in the district are also Late Cretaceous (for example, 92 Ma at the Tolovana Mine and 103 Ma at the Hi-Yu Mine).\n\u003C\u002Fp>\u003Cp>Locality: Grant Mine (SE1\u002F4 section 28, T1N, R2W, Fairbanks D-2 topographic quadrangle), ~0.75 air-miles south of the Ester Dome Road-St. Patrick Road intersection, eastern side of Ester Dome, southwestern Fairbanks Mining District, Tintina Gold Province, Fairbanks North Star Borough, northwest of the city of Fairbanks, central Alaska, USA\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Grant Mine geology mostly synthesized from:\n\u003C\u002Fp>\u003Cp>Freeman & Schaefer (2001) - Alaska resource data file, Fairbanks quadrangle.  United States Geological Survey Open-File Report 2001-426.  355 pp.\n\u003C\u002Fp>\u003Cp>Goldfarb et al. (2007) - Geology and origin of epigenetic lode gold deposits, Tintina Gold Province, Alaska and Yukon.  United States Geological Survey Scientific Investigations Report 2007-5289-A.  18 pp.\n\u003C\u002Fp>\nSwainbank & Clautice (1998) - Alaska’s mineral industry 1997: a summary.  Alaska Division of Geological & Geophysical Surveys Information Circular 43.  12 pp.",2706,1991,{"id":957,"source_url":958,"license_code":523,"credit_html":959,"title":960,"description":961,"author":608,"original_width":962,"original_height":963},27049,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34347277","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34347277\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Carbon Leader Gold Ore, Witwatersrand South Africa 4.jpg","\u003Cp>Carbon Leader Gold Ore with gold (Au) and uraninite (UO2) (black).  This rock is quite radioactive.\n\u003C\u002Fp>\u003Cp>The Witwatersrand area of South Africa produces a significant percentage of the world's gold.  This is a spectacular sample of Precambrian high-grade gold ore from South Africa’s Blyvooruitzicht Gold Mine.  The rock is from the Carbon Leader (also known as the Carbon Leader Reef & Carbon Leader Seam), a blackened, hydrocarbon-rich stromatolitic interval richly impregnated with native gold (Au) and radioactive uraninite\u002Fpitchblende (UO2).  This is a paleoplacer deposit, part of an ancient alluvial fan succession.\n\u003C\u002Fp>\u003Cp>Stratigraphy & Age: Carbon Leader Member, Main Conglomerate, lower Johannesburg Subgroup, lower Central Rand Group, Witwatersrand Supergroup, lower Neoarchean, ~2.9 billion years old.\n\u003C\u002Fp>\nLocality: Blyvooruitzicht Gold Mine, Carletonville Goldfield, West Witwatersrand (“West Wits”), South Africa.",1574,1269,{"id":965,"source_url":966,"license_code":523,"credit_html":967,"title":968,"description":961,"author":608,"original_width":969,"original_height":970},27050,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34347305","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34347305\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Carbon Leader Gold Ore, South Africa 3.jpg",1396,1219,{"id":972,"source_url":973,"license_code":543,"credit_html":974,"title":975,"description":11,"author":11,"original_width":741,"original_height":976},29014,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F128333","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F128333\" rel=\"noopener\">University of Tartu, Natural History Museum\u003C\u002Fa> via Europeana","Gold",870,{"id":978,"source_url":979,"license_code":980,"credit_html":981,"title":982,"description":983,"author":984,"original_width":529,"original_height":985},32186,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=8991296","CC BY 3.0","Rock Currier, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=8991296\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Altaite and Gold - Browns Flat, Bald Mountains, Calaveras County, California, USA.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAltaite\" class=\"extiw\" title=\"en:Altaite\">Altaite\u003C\u002Fa> (gray) and \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Browns Flat, Bald Mt, Calaveras County, California, USA\u003C\u002Fdd>\n\u003Cdd>Description: Specimen is from the collection of C.D. Woodhouse 1974 - Scale at bottom of image is one inch with a rule at one cm.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Rock Currier",968,{"id":987,"source_url":988,"license_code":727,"credit_html":989,"title":990,"description":991,"author":731,"original_width":732,"original_height":733},32190,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202841","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202841\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Altaite with Petzite, Melonite, and Gold (47814843201).jpg","\u003Cp>Colorado, USA\n\u003C\u002Fp>\n\u003Col>\u003Cli>1100\u003C\u002Fli>\u003C\u002Fol>",{"id":993,"source_url":994,"license_code":727,"credit_html":995,"title":996,"description":997,"author":731,"original_width":732,"original_height":733},32191,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202842","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202842\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Altaite with Gold and Coloradoite (47762673532).jpg","\u003Cp>Wright Hargreaves Mine\nOntario, Canada\n\u003C\u002Fp>\n\u003Col>\u003Cli>1099\u003C\u002Fli>\u003C\u002Fol>",{"id":999,"source_url":1000,"license_code":727,"credit_html":1001,"title":1002,"description":1003,"author":731,"original_width":733,"original_height":732},32193,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202844","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202844\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Altaite with Pyrite, Gold, Chalcopyrite, and Molybdenite (47762673972).jpg","\u003Cp>Lakeshore Mine\nOntario, Canada\n\u003C\u002Fp>\n\u003Col>\u003Cli>1097\u003C\u002Fli>\u003C\u002Fol>",{"id":1005,"source_url":1006,"license_code":727,"credit_html":1007,"title":1008,"description":1009,"author":731,"original_width":732,"original_height":733},32195,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202847","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202847\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Altaite with Coloradoite and Gold (47762674322).jpg","\u003Cp>Kirkland Lake\nOntario, Canada\n\u003C\u002Fp>\n\u003Col>\u003Cli>1095\u003C\u002Fli>\u003C\u002Fol>",{"id":1011,"source_url":1012,"license_code":533,"credit_html":1013,"title":1014,"description":1015,"author":537,"original_width":1016,"original_height":1017},33949,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10133205","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10133205\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Arsenopyrite-49053.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FArsenopyrite\" class=\"extiw\" title=\"en:Arsenopyrite\">Arsenopyrite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Triumph Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMariposa_County,_California\" class=\"extiw\" title=\"en:Mariposa County, California\">Mariposa County\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCalifornia\" class=\"extiw\" title=\"en:California\">California\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-82558.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Aesthetic specimen of a spire of Arsenopyrite sprinkled with lustrous coarse Gold crystals averaging 2-3 mm in size. The combination of the numerous Gold crystals, the silver matrix and the white Quartz for accent make this nicely attractive. Unusual! 2.2 x .9 x .9 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",386,800,{"id":1019,"source_url":1020,"license_code":533,"credit_html":1021,"title":1022,"description":1023,"author":537,"original_width":919,"original_height":1024},33956,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10443205","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10443205\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Arsenopyrite-Gold-3d58c.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FArsenopyrite\" class=\"extiw\" title=\"en:Arsenopyrite\">Arsenopyrite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Triumph Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMariposa_County,_California\" class=\"extiw\" title=\"en:Mariposa County, California\">Mariposa County\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCalifornia\" class=\"extiw\" title=\"en:California\">California\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-82558.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: thumbnail, 2.2 x .9 x .9 cm\n\u003Cdl>\u003Cdt>Gold on Arsenopyrite\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>Aesthetic specimen of a spire of Arsenopyrite sprinkled with lustrous coarse Gold crystals averaging 2-3 mm in size. The combination of the numerous Gold crystals, the silver matrix and the white Quartz for accent make this nicely attractive. Unusual!\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",341,{"id":1026,"source_url":1027,"license_code":533,"credit_html":1028,"title":1029,"description":1030,"author":537,"original_width":1017,"original_height":1031},37801,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10465421","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10465421\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Calaverite-Gold-t07-83a.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCalaverite\" class=\"extiw\" title=\"en:Calaverite\">Calaverite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Golden Mine Mines, Kalgoorlie, Australia\u003C\u002Fdd>\n\u003Cdd>Size: small cabinet, 7.3 x 6.4 x 0.7 cm\n\u003Cdl>\u003Cdt>Gold ps. Calaverite\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>A rich slab of matrix rock hosting veins of brilliant gold that has replaced rich calaverite which was there previously. VERY RARE material, and one of the few I have ever seen for sale.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",714,{"id":1033,"source_url":1034,"license_code":533,"credit_html":1035,"title":1036,"description":1030,"author":537,"original_width":919,"original_height":1037},37802,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10465422","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10465422\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Calaverite-Gold-t07-83b.jpg",329,{"id":1039,"source_url":1040,"license_code":523,"credit_html":1041,"title":1042,"description":1043,"author":608,"original_width":1044,"original_height":1045},37804,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952314","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952314\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Native gold-calaverite-coloradoite (Kalgoorlie Mining District, Western Australia) (16584308663).jpg","\u003Cp>Native gold-calaverite-coloradoite from Australia. (CSM 54515, Colorado School of Mines Geology Museum, Golden, Colorado, USA)\n\u003C\u002Fp>\u003Cp>The highly lustrous rock shown above has 3 metallic-lustered minerals in what appears to be quartz.  The gold-colored minerals are native gold (Au) and calaverite (AuTe2 - gold telluride).  The silver-colored mineral is coloradoite (HgTe - mercury telluride).\n\u003C\u002Fp>\nLocality: Kalgoorlie Mining District, Western Australia",2358,1157,{"id":1047,"source_url":1048,"license_code":533,"credit_html":1049,"title":1050,"description":1051,"author":537,"original_width":855,"original_height":1052},50407,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10135924","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10135924\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Conichalcite-60820.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FConichalcite\" class=\"extiw\" title=\"en:Conichalcite\">Conichalcite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Dome Rock Copper Mine, Kalabity homestead area, Olary Province, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSouth_Australia\" class=\"extiw\" title=\"en:South Australia\">South Australia\u003C\u002Fa>, Australia (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-155.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>An excellent and showy combination piece from the famous Dome Rock Copper Mine of South Australia, Australia. Gold flecks are found on one face of the schist matrix, while another face is richly and colorfully covered green conichalcite. 7.8 x 6.0 x 5.5 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",501,{"id":1054,"source_url":1055,"license_code":727,"credit_html":1056,"title":1057,"description":1058,"author":731,"original_width":733,"original_height":732},50897,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118205755","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118205755\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Cosalite with Gold in Quartz (46995655935).jpg","\u003Cp>Wells\nBritish Columbia, Canada\n\u003C\u002Fp>\nS-74-1979",{"id":1060,"source_url":1061,"license_code":727,"credit_html":1062,"title":1063,"description":1064,"author":1065,"original_width":1066,"original_height":1067},52310,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=289839","Eurico Zimbres FGEL\u002FUERJ, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=289839\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","DiamanteEZ.jpg","The \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOppenheimer_Diamond\" class=\"extiw\" title=\"en:Oppenheimer Diamond\">Oppenheimer Diamond\u003C\u002Fa>, named after Ernest Oppenheimer, a gold mining entrepreneur, is one of the biggest uncut diamonds. This diamond is a nearly perfectly-formed yellow diamond crystal weighing about 253.7 carats (50.74 g). It measures approximately 20 × 20 millimeters and was discovered in 1964 at the \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FDu_Toit%27s_Pan\" class=\"extiw\" title=\"en:Du Toit's Pan\">Dutoitspan Mine\u003C\u002Fa>, Kimberly, South Africa.","Eurico Zimbres FGEL\u002FUERJ",440,458,{"id":1069,"source_url":1070,"license_code":523,"credit_html":1071,"title":1072,"description":1073,"author":608,"original_width":1074,"original_height":1075},58603,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=165071900","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=165071900\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Hematite (Ouro Preto area, Minas Gerais State, Brazil) 2.jpg","\"Hematite rose\" from Brazil.\n\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 6000 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>The oxide minerals all contain one or more oxide anions (O-2).\n\u003C\u002Fp>\u003Cp>Hematite is a common iron oxide mineral (Fe2O3).  It varies in appearance, from nonmetallic-lustered and brick red-colored to metallic-lustered and silvery-gray colored.  Brick red hematite is often powdery \u002F earthy or finely granular or oolitic.  Silvery-gray hematite (micaceous hematite) is less common and results from mild to moderate levels of metamorphism.  Hematite ranges in hardness from soft to moderately hard (about 1 to 6 on the Mohs Hardness Scale).  Regardless of a specimen’s color or luster, hematite will always leave a brick red-colored streak, which is its most diagnostic physical property.\n\u003C\u002Fp>\u003Cp>Locality: \"Dom Bosco Mine\", near the town of Ouro Preto, Minas Gerais State, southeastern Brazil\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of hematite:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=1856",2286,1719,{"id":1077,"source_url":1078,"license_code":533,"credit_html":1079,"title":1080,"description":1081,"author":537,"original_width":1017,"original_height":1082},58799,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10137967","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10137967\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Hessite-Gold-76498.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FHessite\" class=\"extiw\" title=\"en:Hessite\">Hessite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Botés, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAlba_County\" class=\"extiw\" title=\"en:Alba County\">Alba County\u003C\u002Fa>, Romania (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-24510.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>WOW! This is an incredible, world-class thumbnail of this very rare silver species! Such pieces are usually 100-200 years old and more. Pristine, aesthetic examples are few and far between in any size, but THIS ONE is a competition level piece for aesthetics, aside from the rarity and history. Note the Smithsonian label showing it is from the Carl Bosch collection. Bosch didnt collect anything bad. Even his small stuff is good, as this exemplifies! 2.1 x 1.7 x 1.5 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",671,{"id":1084,"source_url":1085,"license_code":533,"credit_html":1086,"title":1087,"description":1088,"author":537,"original_width":1089,"original_height":919},58804,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10453002","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10453002\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Hessite-mf11c.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FHessite\" class=\"extiw\" title=\"en:Hessite\">Hessite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Botés, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAlba_County\" class=\"extiw\" title=\"en:Alba County\">Alba County\u003C\u002Fa>, Romania (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-24510.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: thumbnail, 2.1 x 1.7 x 1.5 cm\n\u003Cdl>\u003Cdt>Hessite, Gold\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>WOW! This is an incredible, world-class thumbnail of this very rare silver species! Such pieces are usually 100-200 years old and more. Pristine, aesthetic examples are few and far between in any size, but THIS ONE is a competition level piece for aesthetics, aside from the rarity and history. Note the Smithsonian label showing it is from the Carl Bosch collection. Bosch didnt collect anything bad. Even his small stuff is good, as this exemplifies!\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",333,{"id":1091,"source_url":1092,"license_code":533,"credit_html":1093,"title":1094,"description":1095,"author":537,"original_width":1096,"original_height":1097},59859,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10174344","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10174344\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Opal-290319.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOpal\" class=\"extiw\" title=\"en:Opal\">Opal\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Blue Bird Vein, Blue Bird Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FBull_Hill\" class=\"extiw\" title=\"en:Bull Hill\">Bull Hill\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTeller_County,_Colorado\" class=\"extiw\" title=\"en:Teller County, Colorado\">Teller County\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FColorado\" class=\"extiw\" title=\"en:Colorado\">Colorado\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-214970.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 7.1 x 4.4 x 3.7 cm.\u003C\u002Fdd>\n\u003Cdd>This exceptionally rare, unusual and rich association specimen is from the Blue Bird mine, which is just southeast of Cripple Creek in Colorado. The piece features several very small, micro \"wires\" of Gold which are coated by gemmy, spherical aggregates of colorless\u002Fwhite\u002Fgrey Opal (\"Hyalite\"), and are associated with Chalcopyrite crystals that are coated with Tetrahedrite. The reverse side of the specimen has minor crystals of well known Telluride, Sylvanite along with Dolomite, Celestine, light purple Fluorite, and a small vug with micro reddish-brown spherical aggregates of an unknown mineral. There are at least nine species on this specimen. To find Gold with Opal is rather uncommon in the mineral world, and specimens from this mine are virtually never available for purchase. This piece came from the well-known Colorado collection of Richard A. Kosnar, and his label states that the piece was collected in 1930 by a miner named Wilbur Wassau.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",465,349,{"id":1099,"source_url":1100,"license_code":677,"credit_html":1101,"title":1102,"description":1103,"author":1104,"original_width":1105,"original_height":1106},60681,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=5609784","Géry PARENT, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=5609784\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz 5.jpg","topaz var. bicolor imperial topaz : Vermelhão Mine, Saramenha, Ouro Preto, Mucury Valley, Minas Gerais, Brazil","Géry PARENT",2848,4288,{"id":1108,"source_url":1109,"license_code":533,"credit_html":1110,"title":1111,"description":1112,"author":537,"original_width":1113,"original_height":919},60683,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10130393","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10130393\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-41310.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>A shimmering, golden, terminated gem crystal of imperial topaz, of the classic color. These are difficult to shoot and the crystal is gemmier in person. Weighs 15 grams. The crystal is NOT terminated, but it is GEMMY! 4.5 x 0.9 x 0.9cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",198,{"id":1115,"source_url":1116,"license_code":533,"credit_html":1117,"title":1118,"description":1119,"author":537,"original_width":1120,"original_height":855},60684,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10134172","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10134172\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-49950.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>This is a vibrantly gemmy and brilliant topaz crystal from old workigns at this locality. It weighs almost 60 grams! The crysatl is complete all around save for minor wear on its lower portion, which could in any case be growth contact. the termination is sharp, gemmy, and truly oustanding. VERY FEW imperial topaz crystals of such size reach the market today. 8.6 x 1.8 x 1.2 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",285,{"id":1122,"source_url":1123,"license_code":533,"credit_html":1124,"title":1125,"description":1126,"author":537,"original_width":1127,"original_height":855},60686,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10142367","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10142367\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-137561.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 2.9 x 1.2 x 0.7 cm.\u003C\u002Fdd>\n\u003Cdd>A superb gem crystal of the prized \"imperial\" topaz, with such an intense saturated sherry color that it leans almost towards red in good light. It is complete, terminated, and has super glassy luster. It has the internal scintillations that make these so unique and pretty, and prized by collectors. Weighs 5 grams.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",398,{"id":1129,"source_url":1130,"license_code":533,"credit_html":1131,"title":1132,"description":1133,"author":537,"original_width":1134,"original_height":919},60687,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10144695","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10144695\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-144885.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 2.9 x 1.5 x 1.2 cm.\u003C\u002Fdd>\n\u003Cdd>A CLASSIC, golden-yellow imperial topaz from Ouro Preto, Brazil. This gemmy, lustrous and pristine beauty has a sharp, pyramidal termination, which is particularly gemmy and inclusion-free. 10 grams. Always a desirable gem species.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",272,{"id":1136,"source_url":1137,"license_code":533,"credit_html":1138,"title":1139,"description":1140,"author":537,"original_width":1141,"original_height":1017},60688,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145405","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145405\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-147452.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 1.9 x 0.7 x 0.5 cm.\u003C\u002Fdd>\n\u003Cdd>Very typical crystal, equant and gemmy.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",412,{"id":1143,"source_url":1144,"license_code":533,"credit_html":1145,"title":1146,"description":1147,"author":537,"original_width":1148,"original_height":1017},60689,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145414","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145414\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-147463.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 1.9 x 0.6 x 0.4 cm.\u003C\u002Fdd>\n\u003Cdd>Elongated and very gemmy, with only one minor ding on left edge.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",318,{"id":1150,"source_url":1151,"license_code":533,"credit_html":1152,"title":1153,"description":1154,"author":537,"original_width":1155,"original_height":1017},60690,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145415","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145415\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-147464.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 2.0 x 0.9 x 0.7 cm.\u003C\u002Fdd>\n\u003Cdd>Super color but missing a bit on lower right.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",419,{"id":1157,"source_url":1158,"license_code":533,"credit_html":1159,"title":1160,"description":1161,"author":537,"original_width":1016,"original_height":1017},60691,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145420","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145420\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-147468.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 1.6 x 0.6 x 0.5 cm.\u003C\u002Fdd>\n\u003Cdd>A fine, gemmy crystal with only a tiny ding on the termination.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",{"id":1163,"source_url":1164,"license_code":533,"credit_html":1165,"title":1166,"description":1167,"author":537,"original_width":855,"original_height":1168},60692,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145583","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145583\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-148269.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 2.9 x 1.1 x 0.8 cm\u003C\u002Fdd>\n\u003Cdd>- 2.1 x 0.7 x 0.6 cm. A great set of 14 terminated crystals, 27 grams, of gem imperial topaz! This is cutter-quality material, with the classic sherry\u002Forange color and scintillations from the interior.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",388,{"id":1170,"source_url":1171,"license_code":533,"credit_html":1172,"title":1173,"description":1174,"author":537,"original_width":855,"original_height":636},60693,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145779","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145779\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-149400.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 4.9 x 1.1 x 0.8 cm\u003C\u002Fdd>\n\u003Cdd>(largest). A fine set of 5 imperial topaz crystals. All have the desired golden-sherry color with internal scintillations, and all five are TERMINATED as well. You are looking at a total of 31 grams here, most of it gem material.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",{"id":1176,"source_url":1177,"license_code":533,"credit_html":1178,"title":1179,"description":1180,"author":537,"original_width":919,"original_height":855},60694,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10166080","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10166080\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-244320.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 2.3 x 0.8 x 0.6 cm.\u003C\u002Fdd>\n\u003Cdd>\"Imperial\" topaz from Ouro Preto, Brazil is a \"Holy Grail\" topaz varietal, most collectors look for. This is a rare doubly terminated crystal. This classic, gorgeous, gemmy and lustrous, complete-all-around, striated crystal has beautiful, golden-orange color and excellent lustre and fire. The internal crazing adds character. Very nearly pristine. Weighs 12.53 carats or 2.5 grams.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",{"id":1182,"source_url":1183,"license_code":533,"credit_html":1184,"title":1185,"description":1186,"author":537,"original_width":1187,"original_height":855},60695,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10171128","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10171128\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-271667.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 3.9 x 0.9 x 0.4 cm.\u003C\u002Fdd>\n\u003Cdd>This classic, gorgeous, gemmy and lustrous, complete all-around, striated crystal of “Imperial” Topaz has beautiful, golden-yellow color with a more golden-orange termination. It has excellent lustre and fire. The internal crazing adds character. A highly representative crystal from the renowned locale. Very nearly pristine. Weighs 19.08 carats or nearly 4 grams.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",254,{"id":1189,"source_url":1190,"license_code":533,"credit_html":1191,"title":1192,"description":1193,"author":537,"original_width":1194,"original_height":855},60696,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10171522","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10171522\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-275002.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa> (Var.: Imperial Topaz)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 3.9 x 0.8 x 0.6 cm.\u003C\u002Fdd>\n\u003Cdd>This classic, gorgeous, gemmy and lustrous, complete-all-around, striated crystal has beautiful, golden-orange color and excellent lustre and fire. The internal crazing adds character, as does the classic chisel termination. A highly representative crystal from the renowned locale. Nearly pristine. Weighs 21.79 carats or over 4 grams.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",296,{"id":1196,"source_url":1197,"license_code":533,"credit_html":1198,"title":1199,"description":1200,"author":537,"original_width":1201,"original_height":1017},60697,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10476595","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10476595\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-tz21a.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: thumbnail, 2.5 x 0.7 x 0.6 cm\n\u003Cdl>\u003Cdt>Purple Imperial Topaz\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>A sharp crystal with one of the best glassy terminations in the lot, good color, and bright lustre, pristine except only for a tiny nick in the bottom -left-edge\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",328,{"id":1203,"source_url":1204,"license_code":533,"credit_html":1205,"title":1206,"description":1207,"author":537,"original_width":1208,"original_height":1017},60698,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10476600","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10476600\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz-tz20a.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTopaz\" class=\"extiw\" title=\"en:Topaz\">Topaz\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOuro_Preto\" class=\"extiw\" title=\"en:Ouro Preto\">Ouro Preto\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMinas_Gerais\" class=\"extiw\" title=\"en:Minas Gerais\">Minas Gerais\u003C\u002Fa>, Southeast Region, Brazil (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-423.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: thumbnail, 3.1 x 0.5 x 0.5 cm\n\u003Cdl>\u003Cdt>Purple Imperial Topaz\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>A slender, sleek, totally gemmy and pristine crysatl!\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",243,{"id":1210,"source_url":1211,"license_code":533,"credit_html":1212,"title":1213,"description":1214,"author":1104,"original_width":1215,"original_height":1216},60700,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10957458","Géry PARENT, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10957458\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Topaz 15.jpg","topaz var. imperial topaz var. rose : Vermelhão Mine, Saramenha, Ouro Preto, Mucury Valley, Minas Gerais, Brazil",2430,2501,{"id":1218,"source_url":1219,"license_code":727,"credit_html":1220,"title":1221,"description":1222,"author":731,"original_width":732,"original_height":733},61771,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196507","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196507\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Joséite with Gruenlingite, Gold, and Bismuthinite (46010909475).jpg","\u003Cp>Glacier Gulch\u002FHudson Bay Mountain\u002FNear Smithers\nBritish Columbia, Canada\n\u003C\u002Fp>\nS-89-168",{"id":1224,"source_url":1225,"license_code":523,"credit_html":1226,"title":1227,"description":1228,"author":608,"original_width":1229,"original_height":1230},67508,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34406553","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34406553\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Homestake Mine gold ore, town of Lead, northern Black Hills, western South Dakota (3.6 cm acr.) (14736672692).jpg","\u003Cp>Homestake Mine gold ore (~1.25 cm across) - numerous visible gold blebs in high-grade gold ore sample from the Homestake Mine, town of Lead, northern Black Hills, western South Dakota, USA.\n\u003C\u002Fp>\u003Cp>The largest gold mine in the Americas was the long-lived Homestake Mine in the town of Lead (pronounced “Leed”), South Dakota, USA.  Located in the Lead Window of the northern Black Hills Uplift in western South Dakota, the Homestake Mine produced about 40 million ounces of gold.  The gold at Homestake is almost exclusively confined to the Homestake Formation, a Paleoproterozoic (~1.9-2.0 billion years) sedimentary unit that originally consisted of interbedded Mg-rich siderite iron formation and marlstones.\n\u003C\u002Fp>\nThe Homestake Formation has been strongly deformed & multiply metamorphosed, and many of the original rocks were converted to greenschists (cummingtonite schists).  The gold has been interpreted as having been originally deposited with the iron formation sediments by seafloor volcanogenic exahalative processes.  Slight metamorphic gold mobilization and tight structural folding has resulted in the formation of auriferous greenschist pods along fold axes.",1193,571,{"id":1232,"source_url":1233,"license_code":523,"credit_html":1234,"title":1235,"description":1236,"author":608,"original_width":1237,"original_height":1238},67510,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952361","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952361\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold and quartz (Main Ledge, 3050 Level, Homestake Mine, Lead, Black Hills, South Dakota, USA) 4 (16614618403).jpg","\u003Cp>Gold and quartz from the Black Hills of South Dakota, USA. (SDSMT 5080, South Dakota School of Mines and Technology Museum of Geology, Rapid City, South Dakota, USA)\n\u003C\u002Fp>\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substrance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Gold (Au) is the most prestigious metal known, but it's not the most valuable.  Gold is the only metal that has a deep, rich, metallic yellow color.  Almost all other metals are silvery-colored.  Gold is very rare in crustal rocks - it averages about 5 ppb (parts per billion).  Where gold has been concentrated, it occurs as wires, dendritic crystals, twisted sheets, octahedral crystals, and variably-shaped nuggets.  It most commonly occurs in hydrothermal quartz veins, disseminated in some contact- & hydrothermal-metamorphic rocks, and in placer deposits.  Placers are concentrations of heavy minerals in stream gravels or in cracks on bedrock-floored streams.  Gold has a high specific gravity (about 19), so it easily accumulates in placer deposits.  Its high density allows prospectors to readily collect placer gold by panning.\n\u003C\u002Fp>\u003Cp>In addition to its high density, gold has a high melting point (over 1000º C).  Gold is also relatively soft - about 2.5 to 3 on the Mohs Hardness Scale.  The use of pure gold or high-purity gold in jewelry is not desirable as it easily gets scratched.  The addition of other metals to gold to increase the hardness also alters the unique color of gold.  Gold jewelry made & sold in America doesn’t have the gorgeous rich color of high-purity gold.\n\u003C\u002Fp>\u003Cp>The largest gold mine in the Americas was the long-lived Homestake Mine in the town of Lead (pronounced “Leed”), South Dakota, USA.  Located in the Lead Window of the northern Black Hills Uplift in western South Dakota, the Homestake Mine produced about 40 million ounces of gold.  The gold at Homestake is almost exclusively confined to the Homestake Formation, a Paleoproterozoic (~1.9-2.0 billion years) sedimentary unit that originally consisted of interbedded Mg-rich siderite iron formation and marlstones.\n\u003C\u002Fp>\u003Cp>The Homestake Formation has been strongly deformed & multiply metamorphosed, and many of the original rocks were converted to greenschists (cummingtonite schists).  The gold has been interpreted as having been originally deposited with the iron formation sediments by seafloor volcanogenic exahalative processes.  Slight metamorphic gold mobilization and tight structural folding has resulted in the formation of auriferous greenschist pods along fold axes.\n\u003C\u002Fp>\nLocality: Main Ledge, 3050 Level, Homestake Mine, Lead, northern Black Hills, western South Dakota, USA",3994,2615,{"id":1240,"source_url":1241,"license_code":523,"credit_html":1242,"title":1243,"description":1236,"author":608,"original_width":732,"original_height":1244},67511,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952362","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952362\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold and quartz (Main Ledge, 3050 Level, Homestake Mine, Lead, Black Hills, South Dakota, USA) 3 (17234822895).jpg",2399,{"id":1246,"source_url":1247,"license_code":523,"credit_html":1248,"title":1249,"description":1236,"author":608,"original_width":1250,"original_height":1251},67512,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952363","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952363\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold and quartz (Main Ledge, 3050 Level, Homestake Mine, Lead, Black Hills, South Dakota, USA) 2 (17027399647).jpg",3008,2000,{"id":1253,"source_url":1254,"license_code":523,"credit_html":1255,"title":1256,"description":1236,"author":608,"original_width":1257,"original_height":1258},67513,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952368","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=39952368\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold and quartz (Main Ledge, 3050 Level, Homestake Mine, Lead, Black Hills, South Dakota, USA) 5 (17047268430).jpg",3992,2642,{"id":1260,"source_url":1261,"license_code":523,"credit_html":1262,"title":1263,"description":698,"author":608,"original_width":699,"original_height":700},67514,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022926","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022926\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Homestake Mine gold ore, town of Lead, northern Black Hills, western South Dakota (1.25 cm acr.) (14736970735).jpg",{"id":1265,"source_url":1266,"license_code":523,"credit_html":1267,"title":1268,"description":1269,"author":608,"original_width":1250,"original_height":1251},67524,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87884951","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87884951\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold and quartz (Main Ledge, 3050 Level, Homestake Mine, Lead, Black Hills, South Dakota, USA) 2.jpg","Gold and quartz from the Precambrian of South Dakota, USA. (SDSMT 5080, South Dakota School of Mines and Technology Museum of Geology, Rapid City, South Dakota, USA)\n\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 5500 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Gold (Au) is the most prestigious metal known, but it's not the most valuable.  Gold is the only metal that has a deep, rich, metallic yellow color.  Almost all other metals are silvery-colored.  Gold is very rare in crustal rocks - it averages about 5 ppb (parts per billion).  Where gold has been concentrated, it occurs as wires, dendritic crystals, twisted sheets, octahedral crystals, and variably-shaped nuggets.  It most commonly occurs in hydrothermal quartz veins, disseminated in some contact- & hydrothermal-metamorphic rocks, and in placer deposits.  Placers are concentrations of heavy minerals in stream gravels or in cracks on bedrock-floored streams.  Gold has a high specific gravity (about 19), so it easily accumulates in placer deposits.  Its high density allows prospectors to readily collect placer gold by panning.\n\u003C\u002Fp>\u003Cp>In addition to its high density, gold has a high melting point (over 1000º C).  Gold is also relatively soft - about 2.5 to 3 on the Mohs Hardness Scale.  The use of pure gold or high-purity gold in jewelry is not desirable as it easily gets scratched.  The addition of other metals to gold to increase the hardness also alters the unique color of gold.  Gold jewelry made & sold in America doesn’t have the gorgeous rich color of high-purity gold.\n\u003C\u002Fp>\u003Cp>The largest gold mine in the Americas was the long-lived Homestake Mine in the town of Lead (pronounced “Leed”), South Dakota, USA.  Located in the Lead Window of the northern Black Hills Uplift in western South Dakota, the Homestake Mine produced about 40 million ounces of gold.  The gold at Homestake is almost exclusively confined to the Homestake Formation, a Paleoproterozoic (~1.9-2.0 billion years) sedimentary unit that originally consisted of interbedded Mg-rich siderite iron formation and marlstones.\n\u003C\u002Fp>\u003Cp>The Homestake Formation has been strongly deformed & multiply metamorphosed, and many of the original rocks were converted to greenschists (cummingtonite schists).  The gold has been interpreted as having been originally deposited with the iron formation sediments by seafloor volcanogenic exahalative processes.  Slight metamorphic gold mobilization and tight structural folding has resulted in the formation of auriferous greenschist pods along fold axes.\n\u003C\u002Fp>\u003Cp>Locality: Main Ledge, 3050 Level, Homestake Mine, Lead, northern Black Hills, western South Dakota, USA\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of gold:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=1720",{"id":1271,"source_url":1272,"license_code":523,"credit_html":1273,"title":1274,"description":1275,"author":608,"original_width":1250,"original_height":1251},73599,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=85925228","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=85925228\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Melanterite-rich mine effluent (Mollie Kathleen Gold Mine, Cripple Creek Mining District, Colorado, USA) 5.jpg","The Cripple Creek Gold District of central Colorado is famous for its unusual gold and silver mineralization.  Precious metal mineralization occurs in the Cripple Creek Diatreme, the root zone of a deeply eroded volcano dating to the Early Oligocene (32 Ma).  The dominant lithology at Cripple Creek is phonolite, a scarce, alkaline, intermediate, extrusive igneous rock.  Cripple Creek gold can be found in its native state (Au), but it typically occurs in the form of gold telluride minerals: for example, calaverite - AuTe2, sylvanite - (Au,Ag)2Te4, petzite - Ag3AuTe2, krennerite - (Au,Ag)Te2, and nagyagite - Pb5Au(Sb,Bi)Te2S6).  Silver also occurs in some Cripple Creek minerals, including sylvanite, petzite, krennerite, hessite - Ag2Te, tennantite - (Cu,Ag,Fe,Zn)12As4S13, acanthite - Ag2S, and argentian tetrahedrite - (Cu,Fe,Ag,Zn)12Sb4S13.\n\u003Cp>The greenish material seen in the photo is melanterite-rich mine effluent, which refers to crystals forming on the walls and ceiling of mines.  This is on the ceiling of a deep subsurface gold mine in Colorado.  Mine effluent is not technically composed of minerals, because it is not natural - mines and mine tunnels are manmade constructs.  Melanterite is a greenish-colored hydrous iron sulfate, FeSO4·7H2O.  It can be naturally-occurring if it forms on weathered, natural rock surfaces.  Iron and sulfur are needed to make melanterite.  In the case seen here, the host rocks for the gold-bearing veins are pyritic phonolites.  Pyrite is iron sulfide (fool's gold), FeS2.  Oxidation in the presence of water readily breaks down pyrite.  The oxidation-hydration products include melanterite.  The brownish material in the picture is iron oxide.\n\u003C\u002Fp>\u003Cp>Geologic unit: Cripple Creek Diatreme, Early Oligocene, ~32 Ma\n\u003C\u002Fp>\u003Cp>Locality: ceiling of the 1000' Level of the Mollie Kathleen Gold Mine, east of the town of Cripple Creek, Cripple Creek Mining District, southern Teller County, central Colorado, USA (38° 45' 11.02\" North latitude, 105° 09' 37.96\" West longitude)\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>See info. at:\n\u003C\u002Fp>\nen.wikipedia.org\u002Fwiki\u002FMelanterite",{"id":1277,"source_url":1278,"license_code":553,"credit_html":1279,"title":1280,"description":1281,"author":1282,"original_width":1283,"original_height":1284},75776,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=79366521","Алексей Четверухин и Дарья Филатова, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=79366521\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Золото дураков.jpg","pyrite","Алексей Четверухин и Дарья Филатова",3791,2576,{"id":1286,"source_url":1287,"license_code":533,"credit_html":1288,"title":1289,"description":1290,"author":537,"original_width":1291,"original_height":643},75927,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10168485","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10168485\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Pyroxmangite-257295.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGold\" class=\"extiw\" title=\"en:Gold\">Gold\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FPyroxmangite\" class=\"extiw\" title=\"en:Pyroxmangite\">Pyroxmangite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Sunnyside Mine (American Tunnel; Mogul Mine; Washington Mine; Belle Creole; Gold Prince; Brenneman Mine; Sunnyside Mine Group), Howardsville, Silverton District, San Juan County, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FColorado\" class=\"extiw\" title=\"en:Colorado\">Colorado\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-3687.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 9.2 x 6.4 x 0.4 cm.\u003C\u002Fdd>\n\u003Cdd>This slabbed specimen is one of the few of its kind that I have seen from this mine. It features several patches of \"Cloud Gold\" which is a speckling of small \"dust\"-like areas of Gold which are intergrown with white Quartz and associated with Galena, Sphalerite and Chalcopyrite, but the most interesting aspect of this specimen is the fact that it features pink patches of the rare Manganese Silicate, Pyroxmangite. This association of Gold with Pyroxmangite is very rare, and possibly unique to the Sunnyside mine. From the 2130 Stope, G Level, La Belle Creole Vein of the mine. This specimen was mined in 1966, and comes from the noted Colorado Gold collection of Richard A. Kosnar.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",513,{"id":1293,"source_url":1294,"license_code":533,"credit_html":1295,"title":1296,"description":1290,"author":537,"original_width":1297,"original_height":636},75928,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10168486","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10168486\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold-Pyroxmangite-257296.jpg",401,{"id":1299,"source_url":1300,"license_code":543,"credit_html":1301,"title":1302,"description":1303,"author":1304,"original_width":1305,"original_height":1306},81720,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=23353765","DerHexer, Wikimedia Commons, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=23353765\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Harvard Museum of Natural History. Szenicsite. Jardinera No. 1 Mine, near Inca de Oro, Atacama, Chile (DerHexer) 2012-07-20.jpg","Harvard Museum of Natural History. Szenicsite. Jardinera No. 1 Mine, near Inca de Oro, Atacama, Chile.","DerHexer, Wikimedia Commons",2094,1694,{"id":1308,"source_url":1309,"license_code":727,"credit_html":1310,"title":1311,"description":1312,"author":731,"original_width":732,"original_height":733},82246,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196585","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196585\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Tellurobismuthite with Gold (46200380024).jpg","\u003Cp>Boston Creek, South of Kirkland Lake\nOntario, Canada\n\u003C\u002Fp>\nS-88-150",{"id":1314,"source_url":1315,"license_code":727,"credit_html":1316,"title":1317,"description":1318,"author":731,"original_width":732,"original_height":733},82248,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196598","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196598\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Tellurobismuthite with Gold (46200380134).jpg","\u003Cp>Sullivan Consolidated Mine, Val-d'Or\nQuebec, Canada\n\u003C\u002Fp>\nS-88-146",{"id":1320,"source_url":1321,"license_code":727,"credit_html":1322,"title":1323,"description":1324,"author":731,"original_width":733,"original_height":732},82250,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196628","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118196628\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Tellurobismuthite with Gold and Quartz (46200380464).jpg","\u003Cp>Hedley Yuniman Goldfields, 5 miles northeast of Hedley\nBritish Columbia, Canada\n\u003C\u002Fp>\nS-74-140",{"id":1326,"source_url":1327,"license_code":727,"credit_html":1328,"title":1329,"description":1330,"author":731,"original_width":732,"original_height":733},82252,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202696","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202696\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold with Pyrrhotite and Tellurbismuth (46995502835).jpg","\u003Cp>Porcupine Reef Gold Mines Ltd.\nOntario, Canada\n\u003C\u002Fp>\n\u003Col>\u003Cli>1175\u003C\u002Fli>\u003C\u002Fol>",{"id":1332,"source_url":1333,"license_code":727,"credit_html":1334,"title":1335,"description":1336,"author":731,"original_width":733,"original_height":732},82439,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202811","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202811\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Gold in Quartz with Tetradymite (47814839281).jpg","\u003Cp>Red Mountain Mine, South of Sardis\nWashington, USA\n\u003C\u002Fp>\n\u003Col>\u003Cli>1118\u003C\u002Fli>\u003C\u002Fol>",[1338,1344,1348,1352,1356],{"id":1339,"url":1340,"label":1341,"formula":8,"spacegroup":1342,"year":1343},5608,"\u002Fcif\u002F5608.cif","Suh 1988","F m 3 m",1988,{"id":1345,"url":1346,"label":1347,"formula":8,"spacegroup":1342,"year":501},5618,"\u002Fcif\u002F5618.cif","Wyckoff 1963",{"id":1349,"url":1350,"label":1351,"formula":8,"spacegroup":1342,"year":461},5619,"\u002Fcif\u002F5619.cif","Jette 1935",{"id":1353,"url":1354,"label":1355,"formula":8,"spacegroup":1342,"year":441},5620,"\u002Fcif\u002F5620.cif","Owen 1933",{"id":1357,"url":1358,"label":1359,"formula":8,"spacegroup":1342,"year":416},5621,"\u002Fcif\u002F5621.cif","Davey 1925",[1361,1362,1363,1364,8,1365,1366,1367,1368,1369,1370,1371,1372,1373,1374,1375,1376,975,1377,1378,1379,1380,1381,1382,1383,1384,1385,1386,1387,1388,1389,1390,1391,1392,1393,1394,1395,1396,1397,1398,1399,1400,1401,1402,1403,1404,1405,1406,1407,1408,1409,1410,1411,1412,1413],"Airh","Altın","Arany","Ari","Auksas","Aur","Aurum","Cōztic teōcuitlatl","Dhahabu","Emas","Gediegen Gold","Gedigent Gull","Gediget Guld","Gim","Ginto","Gintu","Goud","Guld","Igolide","Jold","Kîm","Kuarepotiju","Kuld","Kulta","Lò","Oltin","Or","Ór","Òr","Ore (novial name for gold)","Oro","Oru","Ouro","Qızıl","Qori","Quri","Sol","Solji","Urre","Vàng","Wolo","Wólo","Zelts","Zêr","Zern","Złoto","Χρυσός","સોનું","தங்கம்","బంగారం","ಚಿನ್ನ","സ്വര്‍ണ്ണം","ᎠᏕᎸ ᏓᎶᏂᎨ",[1415,1419,1423,1427,1432,1436,1440,1444,1448,1451,1455,1459,1463,1467,1471,1477,1480,1484,1488,1492],{"lang":1416,"names":1417},"az",[1418],"sərbəst qızıl",{"lang":1420,"names":1421},"ca",[1422],"or natiu",{"lang":1424,"names":1425},"cs",[1426],"zlato",{"lang":1428,"names":1429},"de",[1430,1431],"gediegen Gold","Gold, gediegen",{"lang":1433,"names":1434},"es",[1435],"oro nativo",{"lang":1437,"names":1438},"fr",[1439],"or natif",{"lang":1441,"names":1442},"hu",[1443],"termésarany",{"lang":1445,"names":1446},"hy",[1447],"Բնածին ոսկի",{"lang":1449,"names":1450},"it",[1435],{"lang":1452,"names":1453},"ja",[1454],"自然金",{"lang":1456,"names":1457},"ka",[1458],"თვითნაბადი ოქრო",{"lang":1460,"names":1461},"ko",[1462],"자연금",{"lang":1464,"names":1465},"oc",[1466],"aur natiu",{"lang":1468,"names":1469},"pl",[1470],"złoto rodzime",{"lang":1472,"names":1473},"ru",[1474,1475,1476],"золото","золото самородное","Самородное золото",{"lang":1478,"names":1479},"sk",[1426],{"lang":1481,"names":1482},"sl",[1483],"samorodno zlato",{"lang":1485,"names":1486},"tt",[1487],"үзтума алтын",{"lang":1489,"names":1490},"udm",[1491],"аскылдэм зарни",{"lang":1493,"names":1494},"uk",[1495,1496],"золото самородне","самородне золото","Q898406",{"history":1499,"applications":1503},{"markdown":1500,"model_version":1501,"prompt_version":1502,"reviewed_at":11},"No other mineral has shaped human history the way native gold has — as ornament, as money, as the metal that anchored entire economies for nearly three thousand years.\n\nSmall amounts of natural gold were already being gathered in late Paleolithic Spain around 40,000 BCE[1]. By the 5th millennium BCE the metal was being worked deliberately: the oldest gold artefacts in the world come from graves in the Varna Necropolis, on the Bulgarian Black Sea coast[2]. Egyptian goldsmiths followed at the end of the same millennium, and over the course of the 4th millennium BCE they developed smelting — heating the metal to separate it from its host rock[3]. Gold's softness made it workable with stone tools; its refusal to tarnish made it eternal in a way no other early metal was.\n\n### From ornament to money\n\nAround 610 BCE, the kingdom of Lydia in western Anatolia struck the world's earliest coinage, drawing on alluvial gold from the silt of the Pactolus river that ran through the Lydian capital, Sardis[4]. The first Lydian coins were electrum — a natural gold–silver alloy of variable composition. The decisive step came under King Croesus, who ruled from about 585 to 547 BCE[5]. Croesus is credited with issuing the first true gold coins with a standardised purity for general circulation, the **Croeseid**[6]. His engineers learned to purify the metal by heating it with common salt to drive off the silver, producing a coin whose value did not depend on guessing its alloy[7]. The name *Croesus* became a Greek and Persian synonym for a wealthy man[8].\n\nFor the next two millennia, gold travelled the alchemists' workbench as much as the merchant's purse. The alchemists called it **Sol** — the sun. One of their central goals was to produce gold from base metals such as lead, supposedly through the agency of a mythical substance called the philosopher's stone[9].\n\nThe English name has its own slow biography. The word *gold* descends from a Proto-Indo-European root meaning *to shine, to gleam, to be yellow or green*[10], and the Old English form first appears in writing around 725[11]. The chemical symbol **Au** comes from another lineage — the Latin *aurum*, fixed as the international symbol for the element by the Swedish chemist Jöns Jakob Berzelius when he established the modern system of chemical notation in the early 19th century[12].\n\n### The great rushes\n\nOn 24 January 1848, James W. Marshall found shiny metal in the tailrace of a lumber mill he was building for the Sacramento pioneer John Sutter — Sutter's Mill, near Coloma on the American River[13]. Within a year word had crossed every continent, and roughly 300,000 people poured into California from the rest of the United States and abroad, a population shock that pushed California into statehood in the Compromise of 1850[14].\n\nA second great rush opened in July 1886, when George Harrison declared a claim on the farm Langlaagte in the South African Republic[15]. The reef he had stumbled into was the Witwatersrand, the largest gold deposit ever found; the mining camp that grew around it became Johannesburg, which within a decade was the largest city in South Africa and one of the triggers of the Second Boer War of 1899 to 1902[16]. A decade later still, the Klondike Gold Rush of 1896 to 1899 opened the main goldfield along the south flank of the Klondike River in the Yukon Territory, near its confluence with the Yukon River, around what was to become Dawson City[17].\n\nFor most of recorded history, gold *was* money — its rarity, divisibility, and chemical stability made it the natural anchor for currencies. That arrangement ended on a Sunday evening in 1971. On 15 August of that year, President Richard Nixon announced from the White House that the United States would no longer convert dollars held by foreign governments into gold at a fixed rate[18]. The decision effectively dismantled the Bretton Woods system that had governed international finance since the Second World War, and converted the dollar — and by extension every major currency tied to it — into a fiat instrument backed by government promise rather than metal[19].","claude-opus-4-7","1.7.0",{"markdown":1504,"model_version":1501,"prompt_version":1502,"reviewed_at":11},"About half of all newly mined gold is turned into jewellery, roughly two-fifths goes into investment, and the remaining tenth disappears into industry[1].\n\n### In jewellery and investment\n\nThe bulk of mined gold still travels straight to the goldsmith's bench. Because pure gold is too soft to hold a setting or take a polish on a ring band, jewellery gold is alloyed with copper, silver, or palladium and graded by **karat** — a 24ths fraction. Pure gold is 24 karat by definition; common jewellery alloys run at 18K (75% gold), 14K (58.3%), 10K (41.7%) or 9K (37.5%)[2]. The mix of co-metals colours the result: a 75% gold alloy with 25% copper yields red gold; a 22.25% copper \u002F 2.75% silver mix gives the rose-gold tone fashionable in pink-toned jewellery[3].\n\nThe investment share moves as bars, coins and central-bank reserves. Even now that no major currency is redeemable for the metal, gold retains a unique status among all commodities as a long-term store of value[4].\n\n### In industry\n\nMost of the industrial 10% goes into electronics. Gold's combination of high malleability, ductility, resistance to corrosion and most other chemical reactions, and electrical conductivity has made it the standard for corrosion-resistant electrical connectors in computerised devices — its chief industrial use[5]. The same properties earn it work in communications equipment, spacecraft, and jet-aircraft engines, where a contact or coating cannot afford to oxidise[6].\n\nA second domain is dentistry. Gold and high-gold alloys (often around 99.7% pure) remain a viable option for indirect restorations such as crowns and partial-coverage onlays, bonded permanently to the tooth with dental cement[7]. Direct gold-foil fillings are rarely used today because of their expense and the specialist training they demand, though the technique survives[8].\n\nA third runs on gold leaf — gold hammered to roughly 0.1 µm thickness by goldbeating[9]. Architectural gilding still uses leaf to mark important structures, both for the visual effect and because gold's non-reactive nature gives the surface a durable protective finish[10]."]