[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"minerals:one:2571":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":15,"mindat_formula_note":11,"ima_formula":15,"elements":16,"sigelements":19,"key_elements":11,"impurities":20,"cim":21,"ima_status":22,"ima_notes":11,"ima_history":11,"approval_year":11,"publication_year":11,"discovery_year":25,"strunz10ed1":26,"strunz10ed2":27,"strunz10ed3":28,"strunz10ed4":29,"dana8ed1":26,"dana8ed2":30,"dana8ed3":26,"dana8ed4":31,"csystem":32,"cclass":33,"spacegroup":34,"spacegroupset":35,"a":36,"b":37,"c":38,"alpha":39,"beta":39,"gamma":39,"aerror":11,"berror":11,"cerror":11,"alphaerror":11,"betaerror":11,"gammaerror":11,"va3":11,"z":40,"csmetamict":14,"commentcrystal":11,"twinning":41,"tranglide":11,"parting":11,"epitaxidescription":42,"morphology":43,"tlform":11,"hmin":44,"hmax":45,"hardtype":46,"vhnmin":47,"vhnmax":48,"vhnerror":11,"vhng":49,"vhns":11,"commenthard":11,"dmeas":50,"dmeas2":50,"dcalc":51,"dmeaserror":11,"dcalcerror":11,"commentdense":11,"lustre":52,"lustretype":53,"commentluster":54,"diapheny":55,"streak":56,"colour":57,"commentcolor":11,"colors":58,"streak_colors":63,"luminescence":11,"uv":64,"cleavage":65,"cleavagetype":66,"fracturetype":67,"tenacity":68,"commentbreak":11,"opticaltype":11,"opticalsign":11,"opticalalpha":39,"opticalalpha2":39,"opticalalphaerror":11,"opticalbeta":39,"opticalbeta2":39,"opticalbetaerror":11,"opticalgamma":39,"opticalgamma2":39,"opticalgammaerror":11,"opticalomega":39,"opticalomega2":39,"opticalomegaerror":11,"opticalepsilon":39,"opticalepsilon2":39,"opticalepsilonerror":11,"opticaln":39,"opticaln2":39,"opticalnerror":11,"optical2vcalc":39,"optical2vcalc2":39,"optical2vcalcerror":11,"optical2vmeasured":39,"optical2vmeasured2":39,"optical2vmeasurederror":11,"rimin":11,"rimax":11,"opticaldispersion":11,"opticalpleochroism":69,"opticalpleochorismdesc":70,"opticalbirefringence":11,"opticalcomments":11,"opticalcolour":11,"opticalinternal":11,"opticaltropic":71,"opticalanisotropism":72,"opticalbireflectance":11,"opticalextinction":11,"opticalr":73,"specdispm":11,"ir":11,"electrical":11,"magnetism":11,"thermalbehaviour":11,"other":11,"industrial":11,"occurrence":11,"otheroccurrence":74,"type_specimen_store":11,"description_short":75,"aboutname":76,"rock_parent":11,"rock_parent2":11,"rock_root":9,"rock_bgs_code":11,"meteoritical_code":11,"updttime":77,"reviewed_at":11,"variety_of":11,"varieties":78,"group_members":83,"associates":116,"confused_with":267,"type_localities":286,"occurrence_total":287,"citations":288,"images":429,"structures":677,"synonyms":699,"language_names":728,"wikidata_qid":928,"texts":929},2571,"1:1:2571:9","86d81eb2-f739-4fe7-a9a7-bd8f3e2ff1cd","Marcasite","Mrc",0,"mineral",null,29308,50096,false,"FeS\u003Csub>2\u003C\u002Fsub>",[17,18],"Fe","S",[17,18],",Cu,As,","3.9.4",[23,24],"APPROVED","GRANDFATHERED","1845","2","E","B","10a","12","1","Orthorhombic",8,73,"Pnnm ","4.436","5.414","3.381","0",2,"Common on {101}, forming \"swallowtail\" contact twins; this may be repeated to form stellate fivelings. Less common on {011}.","Twinned prismatic marcasite crystals attached along pyrite octahedron edges from Rensselaer, Indiana (Brock and Slater, 1978). See also Rakovan et al. (1995).","Crystals usually tabular on {010}, also pyramidal, faces often curved, frequently twinned; also stalactic, globular, or reniform with radiating internal structure.",6,6.5,3,"915","1099",200,"4.887","4.875","Metallic","Metallic,Sub-Metallic","Frequently iridescence obscures the luster and color","Opaque","Dark-gray to black.","Pale brass-yellow, tin-white on fresh exposures.",[59,60,61,62],"yellow","white","gray","black",[61,62],"Not fluorescent in ultraviolet light","Distinct on {101}. {110} in traces.","Distinct\u002FGood","Conchoidal,Sub-Conchoidal","brittle","Strong","Creamy white, light yellowish white, white with rose-brown tint.","Anisotropic","Strong yellow to light green to dark green","(40.4,44.5) 400,\r\n(41.9,45.4) 420,\r\n(43.4,47.3) 440,\r\n(44.3,50.1) 460,\r\n(45.2,52.8) 480,\r\n(46.3,54.8) 500,\r\n(47.7,56.1) 520,\r\n(48.9,56.3) 540,\r\n(49.5,55.9) 560,\r\n(49.6,55.2) 580,\r\n(49.5,54.8) 600,\r\n(49.2,54.8) 620,\r\n(48.7,53.8) 640,\r\n(47.9,52.9) 660,\r\n(47.2,51.9) 680,\r\n(46.6,51.2) 700","Most frequently found in sedimentary rocks and coal beds, as a replacement mineral forming fossils, it is a mineral of low-temperature, near-surface, environments, forming from acid solutions.  Pyrite, the more stable form of FeS2, forms under conditions of higher temperatures and lower acidity or alkaline environments.","Marcasite Group.\r\n\r\nThe orthorhombic polymorph of isometric (cubic) pyrite. A common natural disulfide. Compare UM1997-43-S:Fe.\r\n\r\nCrystals common, metallic pale brass-yellow colored, tabular or pyramidal, often with curved faces and often deeply stria...","Early use of the word marcasite seems to have been unspecific. The word is Arabic or Moorish and was applied to pyrite and similar metallic bronze colored minerals. \r\n\r\nWalter Pope (1665) mentioned marcasite occurring in the mercury ores of the Idria Mine, Cividale del Friuli in the Julian Alps of Slovenia: \"There are also several Marcasites and stones, which seem to have specks of Gold in them, but upon trial they say, they find none in them. These round stones are some of them very ponderous, and well impregnated with Mercury; others light, having little or none in them.\"\r\n\r\nThe mercury ore at Idria does contain metallic golden specks of what is now called marcasite, but it also has metallic golden pyrite. Johnathan Hill used the name marcasite in 1771, but his usage was also indiscriminate and was a term for any massive \"pyrites\" or \"mundic\". In 1845, Wilhelm Karl von Haidinger defined marcasite as the mineral is known today.","2026-03-28 15:04:59",[79],{"id":80,"name":81,"entrytype":40,"csystem":11,"ima_formula":11,"mindat_formula":82,"hmin":11,"hmax":11,"dmeas":39,"dcalc":39,"primary_image_id":11},2429,"Lonchidite","Fe(S,As)\u003Csub>2\u003C\u002Fsub>",[84,91,98,104,109],{"id":85,"name":86,"entrytype":9,"csystem":32,"ima_formula":87,"mindat_formula":87,"hmin":44,"hmax":45,"dmeas":88,"dcalc":89,"primary_image_id":90},1527,"Ferroselite","FeSe\u003Csub>2\u003C\u002Fsub>","7.20","7.139",7558,{"id":92,"name":93,"entrytype":9,"csystem":32,"ima_formula":94,"mindat_formula":94,"hmin":46,"hmax":95,"dmeas":39,"dcalc":96,"primary_image_id":97},1612,"Frohbergite","FeTe\u003Csub>2\u003C\u002Fsub>",4,"8.057",9446,{"id":99,"name":100,"entrytype":9,"csystem":32,"ima_formula":101,"mindat_formula":101,"hmin":102,"hmax":45,"dmeas":39,"dcalc":103,"primary_image_id":11},2288,"Kullerudite","NiSe\u003Csub>2\u003C\u002Fsub>",5.5,"6.72",{"id":105,"name":106,"entrytype":9,"csystem":32,"ima_formula":107,"mindat_formula":107,"hmin":102,"hmax":102,"dmeas":39,"dcalc":108,"primary_image_id":11},2595,"Mattagamite","CoTe\u003Csub>2\u003C\u002Fsub>","8.00",{"id":110,"name":111,"entrytype":9,"csystem":32,"ima_formula":112,"mindat_formula":112,"hmin":40,"hmax":113,"dmeas":11,"dcalc":114,"primary_image_id":115},47038,"Petříčekite","CuSe\u003Csub>2\u003C\u002Fsub>",2.5,"6.673",8063,[117,126,134,138,147,154,161,168,176,184,193,194,202,209,215,222,228,236,244,251,258],{"id":118,"name":119,"entrytype":9,"csystem":120,"ima_formula":121,"mindat_formula":122,"hmin":123,"hmax":40,"dmeas":39,"dcalc":124,"primary_image_id":125},162,"Alunogen","Triclinic","Al\u003Csub>2\u003C\u002Fsub>(SO\u003Csub>4\u003C\u002Fsub>)\u003Csub>3\u003C\u002Fsub>(H\u003Csub>2\u003C\u002Fsub>O)\u003Csub>12\u003C\u002Fsub> · 5H\u003Csub>2\u003C\u002Fsub>O","Al\u003Csub>2\u003C\u002Fsub>(SO\u003Csub>4\u003C\u002Fsub>)\u003Csub>3\u003C\u002Fsub>·17H\u003Csub>2\u003C\u002Fsub>O",1.5,"1.732",29065,{"id":127,"name":128,"entrytype":9,"csystem":129,"ima_formula":130,"mindat_formula":130,"hmin":40,"hmax":40,"dmeas":131,"dcalc":132,"primary_image_id":133},645,"Berzelianite","Isometric","Cu\u003Csub>2-x\u003C\u002Fsub>Se (x ≈ 0.12)","6.71","7.28",3181,{"id":135,"name":136,"entrytype":40,"csystem":11,"ima_formula":11,"mindat_formula":11,"hmin":11,"hmax":11,"dmeas":11,"dcalc":11,"primary_image_id":137},9424,"Bitumen",36039,{"id":139,"name":140,"entrytype":9,"csystem":141,"ima_formula":142,"mindat_formula":143,"hmin":46,"hmax":46,"dmeas":144,"dcalc":145,"primary_image_id":146},859,"Calcite","Trigonal","Ca(CO\u003Csub>3\u003C\u002Fsub>)","CaCO\u003Csub>3\u003C\u002Fsub>","2.7102","2.711",4401,{"id":148,"name":149,"entrytype":9,"csystem":32,"ima_formula":150,"mindat_formula":150,"hmin":113,"hmax":113,"dmeas":151,"dcalc":152,"primary_image_id":153},882,"Canfieldite","Ag\u003Csub>8\u003C\u002Fsub>SnS\u003Csub>6\u003C\u002Fsub>","6.2","6.311",4541,{"id":155,"name":156,"entrytype":9,"csystem":141,"ima_formula":157,"mindat_formula":157,"hmin":40,"hmax":113,"dmeas":158,"dcalc":159,"primary_image_id":160},1052,"Cinnabar","HgS","8.176","8.20",5743,{"id":162,"name":163,"entrytype":9,"csystem":129,"ima_formula":164,"mindat_formula":164,"hmin":95,"hmax":165,"dmeas":39,"dcalc":166,"primary_image_id":167},1097,"Cobaltpentlandite","Co\u003Csub>9\u003C\u002Fsub>S\u003Csub>8\u003C\u002Fsub>",4.5,"5.22",6016,{"id":169,"name":170,"entrytype":9,"csystem":141,"ima_formula":171,"mindat_formula":171,"hmin":172,"hmax":95,"dmeas":173,"dcalc":174,"primary_image_id":175},1304,"Dolomite","CaMg(CO\u003Csub>3\u003C\u002Fsub>)\u003Csub>2\u003C\u002Fsub>",3.5,"2.84","2.876",5744,{"id":177,"name":178,"entrytype":9,"csystem":179,"ima_formula":180,"mindat_formula":180,"hmin":46,"hmax":95,"dmeas":181,"dcalc":182,"primary_image_id":183},1451,"Famatinite","Tetragonal","Cu\u003Csub>3\u003C\u002Fsub>SbS\u003Csub>4\u003C\u002Fsub>","4.635","4.66",8313,{"id":185,"name":186,"entrytype":9,"csystem":187,"ima_formula":188,"mindat_formula":189,"hmin":95,"hmax":165,"dmeas":190,"dcalc":191,"primary_image_id":192},1476,"Ferberite","Monoclinic","Fe\u003Csup>2+\u003C\u002Fsup>(WO\u003Csub>4\u003C\u002Fsub>)","FeWO\u003Csub>4\u003C\u002Fsub>","7.58","7.6",8464,{"id":85,"name":86,"entrytype":9,"csystem":32,"ima_formula":87,"mindat_formula":87,"hmin":44,"hmax":45,"dmeas":88,"dcalc":89,"primary_image_id":90},{"id":195,"name":196,"entrytype":9,"csystem":129,"ima_formula":197,"mindat_formula":198,"hmin":46,"hmax":172,"dmeas":199,"dcalc":200,"primary_image_id":201},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":203,"name":204,"entrytype":9,"csystem":129,"ima_formula":205,"mindat_formula":205,"hmin":95,"hmax":165,"dmeas":206,"dcalc":207,"primary_image_id":208},1747,"Greigite","Fe\u003Csup>2+\u003C\u002Fsup>Fe\u003Csup>3+\u003C\u002Fsup>\u003Csub>2\u003C\u002Fsub>S\u003Csub>4\u003C\u002Fsub>","4.049","4.079",10455,{"id":210,"name":211,"entrytype":9,"csystem":187,"ima_formula":212,"mindat_formula":212,"hmin":40,"hmax":113,"dmeas":213,"dcalc":213,"primary_image_id":214},2434,"Lorándite","TlAsS\u003Csub>2\u003C\u002Fsub>","5.53",14733,{"id":216,"name":217,"entrytype":9,"csystem":129,"ima_formula":218,"mindat_formula":219,"hmin":102,"hmax":102,"dmeas":220,"dcalc":221,"primary_image_id":11},47656,"Paragersdorffite","NiAsS","Ni(As,S)\u003Csub>2\u003C\u002Fsub>","5.9","5.966",{"id":223,"name":224,"entrytype":9,"csystem":129,"ima_formula":15,"mindat_formula":15,"hmin":44,"hmax":45,"dmeas":225,"dcalc":226,"primary_image_id":227},3314,"Pyrite","4.8","5.01",20239,{"id":229,"name":230,"entrytype":9,"csystem":141,"ima_formula":231,"mindat_formula":231,"hmin":232,"hmax":232,"dmeas":233,"dcalc":234,"primary_image_id":235},3337,"Quartz","SiO\u003Csub>2\u003C\u002Fsub>",7,"2.65","2.66",30579,{"id":237,"name":238,"entrytype":9,"csystem":187,"ima_formula":239,"mindat_formula":240,"hmin":40,"hmax":46,"dmeas":241,"dcalc":242,"primary_image_id":243},3469,"Rozenite","Fe\u003Csup>2+\u003C\u002Fsup>(SO\u003Csub>4\u003C\u002Fsub>) · 4H\u003Csub>2\u003C\u002Fsub>O","FeSO\u003Csub>4\u003C\u002Fsub>·4H\u003Csub>2\u003C\u002Fsub>O","2.293","2.29",21251,{"id":245,"name":246,"entrytype":9,"csystem":129,"ima_formula":247,"mindat_formula":247,"hmin":172,"hmax":95,"dmeas":248,"dcalc":249,"primary_image_id":250},3727,"Sphalerite","ZnS","3.9","4.096",66200,{"id":252,"name":253,"entrytype":9,"csystem":32,"ima_formula":254,"mindat_formula":254,"hmin":40,"hmax":40,"dmeas":255,"dcalc":256,"primary_image_id":257},3782,"Stibnite","Sb\u003Csub>2\u003C\u002Fsub>S\u003Csub>3\u003C\u002Fsub>","4.63","4.625",18319,{"id":259,"name":260,"entrytype":9,"csystem":141,"ima_formula":261,"mindat_formula":262,"hmin":263,"hmax":123,"dmeas":264,"dcalc":265,"primary_image_id":266},4136,"Valleriite","2[(Fe,Cu)S] · 1.53[(Mg,Al)(OH)\u003Csub>2\u003C\u002Fsub>]","(Fe\u003Csup>2+\u003C\u002Fsup>,Cu)\u003Csub>4\u003C\u002Fsub>(Mg,Al)\u003Csub>3\u003C\u002Fsub>S\u003Csub>4\u003C\u002Fsub>(OH,O)\u003Csub>6\u003C\u002Fsub>",1,"3.14","3.21",27216,[268,269,270,277],{"id":110,"name":111,"entrytype":9,"csystem":32,"ima_formula":112,"mindat_formula":112,"hmin":40,"hmax":113,"dmeas":11,"dcalc":114,"primary_image_id":115},{"id":223,"name":224,"entrytype":9,"csystem":129,"ima_formula":15,"mindat_formula":15,"hmin":44,"hmax":45,"dmeas":225,"dcalc":226,"primary_image_id":227},{"id":271,"name":272,"entrytype":9,"csystem":32,"ima_formula":273,"mindat_formula":273,"hmin":102,"hmax":44,"dmeas":274,"dcalc":275,"primary_image_id":276},3357,"Rammelsbergite","NiAs\u003Csub>2\u003C\u002Fsub>","7.0","7.091",20522,{"id":278,"name":279,"entrytype":9,"csystem":32,"ima_formula":280,"mindat_formula":281,"hmin":165,"hmax":282,"dmeas":283,"dcalc":284,"primary_image_id":285},3500,"Safflorite","CoAs\u003Csub>2\u003C\u002Fsub>","(Co,Ni,Fe)As\u003Csub>2\u003C\u002Fsub>",5,"7.2","7.471",21407,[],5785,[289,293,297,302,306,310,314,318,323,328,332,336,341,346,350,354,358,363,368,373,376,381,385,389,394,398,402,406,410,415,419,424],{"id":290,"year":291,"html":292,"doi":11},16116333,1665,"Pope, Walter (1665) Extract of a letter, lately written from Venice by the learned Doctor Walter Pope, to the Reverend Dean of Rippon, Doctor John Wilkins, concerning the mines of mercury in Friuli; and a way of producing wind by the fall of water: Philosophical Transactions: May 30, 1665: 1(2): 21-26.",{"id":294,"year":295,"html":296,"doi":11},519906,1931,"Buerger, M. J. (1931) The crystal structure of marcasite. \u003Ci>American Mineralogist\u003C\u002Fi>,  16 (9) 361-395 \u003Ca target='_blank' href='http:\u002F\u002Fwww.minsocam.org\u002Fammin\u002FAM16\u002FAM16_361.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":298,"year":299,"html":300,"doi":301},7144,1932,"Bannister, F. A. (1932) The distinction of pyrite from marcasite in nodular growths. \u003Ci>Mineralogical Magazine and Journal of the Mineralogical Society\u003C\u002Fi>,  23 (138) 179-187 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1180\u002Fminmag.1932.023.138.04'>doi:10.1180\u002Fminmag.1932.023.138.04\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002FMinMag\u002FVolume_23\u002F23-138-179.pdf' class='refpdflink'>\u003C\u002Fa>","10.1180\u002Fminmag.1932.023.138.04",{"id":303,"year":304,"html":305,"doi":11},520171,1934,"Buerger, M. J. (1934) The pyrite-marcasite relation. \u003Ci>American Mineralogist\u003C\u002Fi>,  19 (2) 37-61 \u003Ca target='_blank' href='http:\u002F\u002Fwww.minsocam.org\u002Fammin\u002FAM19\u002FAM19_37.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":307,"year":308,"html":309,"doi":11},520556,1937,"Buerger, M. J. (1937) A common orientation and a classification for crystals based upon a marcasite-like packing. \u003Ci>American Mineralogist\u003C\u002Fi>,  22 (1) 48-56 \u003Ca target='_blank' href='http:\u002F\u002Fwww.minsocam.org\u002Fammin\u002FAM22\u002FAM22_48.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":311,"year":312,"html":313,"doi":11},1118651,1944,"Palache, Charles, Berman, Harry, Frondel, Clifford (1944) \u003Ci>The System of Mineralogy\u003C\u002Fi> (7th ed.) Vol. 1 - Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, New York.",{"id":315,"year":316,"html":317,"doi":11},523125,1958,"Kopp, O. C., Kerr, P. F. (1958) Differential thermal analysis of pyrite and marcasite. \u003Ci>American Mineralogist\u003C\u002Fi>,  43 (11-12) 1079-1097 \u003Ca target='_blank' href='http:\u002F\u002Fwww.minsocam.org\u002Fammin\u002FAM43\u002FAM43_1079.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":319,"year":320,"html":321,"doi":322},16496710,1973,"Brostigen, G., Kjekshus, A., Rømming, Chr., Gronowitz, Salo, Koskikallio, Jouko, Swahn, Carl-Gunnar (1973) Compounds with the Marcasite Type Crystal Structure. VIII. Redetermination of the Prototype. \u003Ci>Acta Chemica Scandinavica\u003C\u002Fi>, 27. 2791-2796 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.3891\u002Facta.chem.scand.27-2791'>doi:10.3891\u002Facta.chem.scand.27-2791\u003C\u002Fa>","10.3891\u002Facta.chem.scand.27-2791",{"id":324,"year":325,"html":326,"doi":327},109016,1975,"Fleet, M. E. (1975) Structural chemistry of marcasite and pyrite type phases. \u003Ci>Zeitschrift für Kristallographie\u003C\u002Fi>,  142 (5-6). 332 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1524\u002Fzkri.1975.142.5-6.332'>doi:10.1524\u002Fzkri.1975.142.5-6.332\u003C\u002Fa>","10.1524\u002Fzkri.1975.142.5-6.332",{"id":329,"year":325,"html":330,"doi":331},10714421,"Lutz, H. D.; Willich, P. (1975) Gitterschwingungsspektren. XV. FIR-Spektren und Schwingungsanalyse von FeS\u003Csub>2\u003C\u002Fsub>-Markasit \u002F Lattice Vibration Spectra. XV. FIR-Spectra and Vibration Analysis of FeS\u003Csub>2\u003C\u002Fsub> Marcasite. \u003Ci>Zeitschrift für Naturforschung A\u003C\u002Fi>,  30 (11). 1458-1461 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1515\u002Fzna-1975-1114'>doi:10.1515\u002Fzna-1975-1114\u003C\u002Fa>","10.1515\u002Fzna-1975-1114",{"id":333,"year":334,"html":335,"doi":11},527003,1978,"Brock, Kenneth J., Slater, Larry D. (1978) Epitaxial marcasite on pyrite from Rensselaer, Indiana. \u003Ci>American Mineralogist\u003C\u002Fi>,  63 (1-2) 210-212 \u003Ca target='_blank' href='http:\u002F\u002Fwww.minsocam.org\u002Fammin\u002FAM63\u002FAM63_210.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":337,"year":338,"html":339,"doi":340},341474,1986,"Murowchick, James B., Barnes, H.L. (1986) Marcasite precipitation from hydrothermal solutions. \u003Ci>Geochimica et Cosmochimica Acta\u003C\u002Fi>,  50 (12) 2615-2629 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002F0016-7037(86)90214-0'>doi:10.1016\u002F0016-7037(86)90214-0\u003C\u002Fa>","10.1016\u002F0016-7037(86)90214-0",{"id":342,"year":343,"html":344,"doi":345},343665,1991,"Schoonen, M. A. A., Barnes, H. L. (1991) Reactions forming pyrite and marcasite from solution: I. Nucleation of FeS2 below 100°C. \u003Ci>Geochimica et Cosmochimica Acta\u003C\u002Fi>,  55 (6) 1495-1504 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002F0016-7037(91)90122-l'>doi:10.1016\u002F0016-7037(91)90122-l\u003C\u002Fa>","10.1016\u002F0016-7037(91)90122-l",{"id":347,"year":343,"html":348,"doi":349},343667,"Schoonen, M. A. A., Barnes, H. L. (1991) Reactions forming pyrite and marcasite from solution: II. Via FeS precursors below 100°C. \u003Ci>Geochimica et Cosmochimica Acta\u003C\u002Fi>,  55 (6) 1505-1514 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002F0016-7037(91)90123-m'>doi:10.1016\u002F0016-7037(91)90123-m\u003C\u002Fa>","10.1016\u002F0016-7037(91)90123-m",{"id":351,"year":343,"html":352,"doi":353},151979,"Lutz, H.D.; Müller, B. (1991) Lattice vibration spectra. LXVIII. Single-crystal Raman spectra of marcasite-type iron chalcogenides and pnictides, FeX2 (X=S, Se, Te; P, As, Sb). \u003Ci>Physics and Chemistry of Minerals\u003C\u002Fi>,  18 (4). 265-268 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1007\u002Fbf00202579'>doi:10.1007\u002Fbf00202579\u003C\u002Fa>","10.1007\u002Fbf00202579",{"id":355,"year":343,"html":356,"doi":357},343502,"Schoonen, M.A.A, Barnes, H.L (1991) Mechanisms of pyrite and marcasite formation from solution: III. Hydrothermal processes. \u003Ci>Geochimica et Cosmochimica Acta\u003C\u002Fi>,  55 (12) 3491-3504 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002F0016-7037(91)90050-f'>doi:10.1016\u002F0016-7037(91)90050-f\u003C\u002Fa>","10.1016\u002F0016-7037(91)90050-f",{"id":359,"year":360,"html":361,"doi":362},228070,1992,"Murowchick, James B. (1992) Marcasite inversion and the petrographic determination of pyrite ancestry. \u003Ci>Economic Geology\u003C\u002Fi>,  87 (4) 1141-1152 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2113\u002Fgsecongeo.87.4.1141'>doi:10.2113\u002Fgsecongeo.87.4.1141\u003C\u002Fa>","10.2113\u002Fgsecongeo.87.4.1141",{"id":364,"year":365,"html":366,"doi":367},15980,1993,"Drapela, T., Beran, A. (1993) Reflected light examination of marcasite and löllingite. \u003Ci>Mineralogy and Petrology\u003C\u002Fi>,  48 (2) 269-274 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1007\u002Fbf01163103'>doi:10.1007\u002Fbf01163103\u003C\u002Fa>","10.1007\u002Fbf01163103",{"id":369,"year":370,"html":371,"doi":372},345572,1995,"Rakovan, John, Schoonen, Martin A. A., Reeder, Richard J., Tyrna, Paul, Nelson, Daniel O. (1995) Epitaxial overgrowths of marcasite on pyrite from the Tunnel and Reservoir Project, Chicago, Illinois, USA: Implications for marcasite growth. \u003Ci>Geochimica et Cosmochimica Acta\u003C\u002Fi>,  59 (2) 343-346 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002F0016-7037(94)00320-l'>doi:10.1016\u002F0016-7037(94)00320-l\u003C\u002Fa>","10.1016\u002F0016-7037(94)00320-l",{"id":374,"year":370,"html":375,"doi":11},12908776,"Richards, R. Peter, Clopton, Edwin L., Jaszczak, John A. (1995) Pyrite and Marcasite Intergrowths from Northern Illinois, in \u003Ci>March - April 1995\u003C\u002Fi>. \u003Ci>The Mineralogical Record\u003C\u002Fi>,  26 (2) Tucson. 129-138",{"id":377,"year":378,"html":379,"doi":380},393391,1996,"Dodony, Istvan, Posfal, Mihaly, Buseck, Peter R. (1996) Structural relationship between pyrite and marcasite. \u003Ci>American Mineralogist\u003C\u002Fi>,  81 (1) 119-125 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2138\u002Fam-1996-1-215'>doi:10.2138\u002Fam-1996-1-215\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fam\u002Fvol81\u002FAM81_119.pdf' class='refpdflink'>\u003C\u002Fa>","10.2138\u002Fam-1996-1-215",{"id":382,"year":383,"html":384,"doi":11},1118654,1997,"Gaines, Richard V.; Skinner, H. Catherine W.; Foord, Eugene E.; Mason, Brian; Rosenzweig, Abraham; King, Vandall T. (1997) \u003Ci>Dana's New Mineralogy\u003C\u002Fi> (8th ed.). Wiley-Interscience. 1872 pp.",{"id":386,"year":383,"html":387,"doi":388},393559,"Fleet, Michael E., Mumin, A. Hamid (1997) Gold-bearing arsenian pyrite and marcasite and arsenopyrite from Carlin Trend gold deposits and laboratory synthesis. \u003Ci>American Mineralogist\u003C\u002Fi>,  82 (1) 182-193 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2138\u002Fam-1997-1-220'>doi:10.2138\u002Fam-1997-1-220\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fam\u002Fvol82\u002FAM82_182.pdf' class='refpdflink'>\u003C\u002Fa>","10.2138\u002Fam-1997-1-220",{"id":390,"year":391,"html":392,"doi":393},9903057,2001,"Uhlig, I, Szargan, R, Nesbitt, H.W, Laajalehto, K (2001) Surface states and reactivity of pyrite and marcasite. \u003Ci>Applied Surface Science\u003C\u002Fi>, 179. 222-229 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002Fs0169-4332(01)00283-5'>doi:10.1016\u002Fs0169-4332(01)00283-5\u003C\u002Fa>","10.1016\u002Fs0169-4332(01)00283-5",{"id":395,"year":396,"html":397,"doi":11},16965834,2005,"(2005) Marcasite. \u003Ci>Handbook of Mineralogy\u003C\u002Fi>. Mineralogical Society of America \u003Ca target='_blank' href='https:\u002F\u002Fwww.handbookofmineralogy.org\u002Fpdfs\u002Fmarcasite.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":399,"year":400,"html":401,"doi":11},16120936,2008,"Cordua, W.S. (2008) Marcasite - pyrite's evil twin. \u003Ci>Leaverite News\u003C\u002Fi>,  33 (10). 6-7",{"id":403,"year":400,"html":404,"doi":405},396084,"Yang, H., Downs, R. T. (2008) Crystal structure of glaucodot, (Co,Fe)AsS, and its relationships to marcasite and arsenopyrite. \u003Ci>American Mineralogist\u003C\u002Fi>,  93 (7) 1183-1186 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2138\u002Fam.2008.2966'>doi:10.2138\u002Fam.2008.2966\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fam\u002Fvol93\u002FAM93_1183.pdf' class='refpdflink'>\u003C\u002Fa>","10.2138\u002Fam.2008.2966",{"id":407,"year":400,"html":408,"doi":409},16106102,"Yang, Hexiong, Downs, Robert T., Eichler, Carla (2008) Safflorite, (Co,Ni,Fe)As\u003Csub>2\u003C\u002Fsub>, isomorphous with marcasite. \u003Ci>Acta Crystallographica Section E Structure Reports Online\u003C\u002Fi>,  64 (9). i62 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1107\u002Fs1600536808026688'>doi:10.1107\u002Fs1600536808026688\u003C\u002Fa>","10.1107\u002Fs1600536808026688",{"id":411,"year":412,"html":413,"doi":414},16116354,2014,"Schmøkel, Mette S., Bjerg, Lasse, Cenedese, Simone, Jørgensen, Mads R. V., Chen, Yu-Sheng, Overgaard, Jacob, Iversen, Bo B. (2014) Atomic properties and chemical bonding in the pyrite and marcasite polymorphs of FeS\u003Csub>2\u003C\u002Fsub>: a combined experimental and theoretical electron density study. \u003Ci>Chem. Sci.\u003C\u002Fi>,  5 (4). 1408-1421 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1039\u002Fc3sc52977k'>doi:10.1039\u002Fc3sc52977k\u003C\u002Fa>","10.1039\u002Fc3sc52977k",{"id":416,"year":412,"html":417,"doi":418},8456233,"Overgaard, Jacob, Schmøkel, Mette, Bjerg, Lasse, Cenedese, Simone, Jørgensen, Mads, Chen, Yu-Sheng, Iversen, Bo (2014) Synchrotron charge density studies of chemical bonding in the polymorphs of FeS2. \u003Ci>Acta Crystallographica Section A Foundations and Advances\u003C\u002Fi>,  70 (a1). C1338 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1107\u002Fs2053273314086616'>doi:10.1107\u002Fs2053273314086616\u003C\u002Fa>","10.1107\u002Fs2053273314086616",{"id":420,"year":421,"html":422,"doi":423},16630845,2023,"Chivers, Tristram, Oakley, Richard T. (2023) Structures and Spectroscopic Properties of Polysulfide Radical Anions: A Theoretical Perspective. \u003Ci>Molecules\u003C\u002Fi>,  28 (15). 5654 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.3390\u002Fmolecules28155654'>doi:10.3390\u002Fmolecules28155654\u003C\u002Fa>","10.3390\u002Fmolecules28155654",{"id":425,"year":426,"html":427,"doi":428},19172252,2025,"Ferreira, Amira R.; González-Jiménez, José María; Yesares, Lola; Blanco-Quintero, Idael F.; Piña, Rubén; Gervilla, Fernando (2025) Nanogeochemistry of Ni, Co, and Cu in zoned marcasite-pyrite crystals. \u003Ci>American Mineralogist\u003C\u002Fi>,  110 (11). 1737-1755 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2138\u002Fam-2024-9508'>doi:10.2138\u002Fam-2024-9508\u003C\u002Fa>","10.2138\u002Fam-2024-9508",[430,440,447,457,466,471,480,485,495,499,506,511,519,527,534,541,549,558,566,573,582,590,597,605,612,619,628,637,646,656,662,669],{"id":431,"source_url":432,"license_code":433,"credit_html":434,"title":435,"description":436,"author":437,"original_width":438,"original_height":439},15420,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7229356","CC BY-SA 4.0","Didier Descouens, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7229356\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","MarcassiteII.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa> from chalk \n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality : \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCap_Blanc_Nez\" class=\"extiw\" title=\"en:Cap Blanc Nez\">Cap Blanc Nez\u003C\u002Fa> France.\u003C\u002Fdd>\n\u003Cdd>Size :8x6cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Didier Descouens",4592,3056,{"id":441,"source_url":442,"license_code":443,"credit_html":444,"title":7,"description":11,"author":11,"original_width":445,"original_height":446},30159,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F59741","CC BY 4.0","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F59741\" rel=\"noopener\">Department of Geology, TalTech\u003C\u002Fa> via Europeana",1000,662,{"id":448,"source_url":449,"license_code":450,"credit_html":451,"title":452,"description":453,"author":454,"original_width":455,"original_height":456},64911,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=854149","CC BY-SA 3.0","Brudersohn (selbst fotografiert 13. März 2005), via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=854149\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Markasit2.JPG","Mineral marcasite, width: 21 mm, location: clay layers in the gypsum opencast mine in Weenzen, Lower Saxony, Germany","Brudersohn (selbst fotografiert 13. März 2005)",880,703,{"id":458,"source_url":459,"license_code":450,"credit_html":460,"title":461,"description":462,"author":463,"original_width":464,"original_height":465},15421,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10129907","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10129907\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite-40471.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FDundas\" class=\"extiw\" title=\"en:Dundas\">Dundas\u003C\u002Fa>, Wentworth County, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOntario\" class=\"extiw\" title=\"en:Ontario\">Ontario\u003C\u002Fa>, Canada (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-23990.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>An old Flambrough Quarry piece -- this one, a beautifully irridescent cluster of marcasite crystals (much prettier in person) perched on the edge of a shard of matrix like a flower! 3.3 x 2.1 x 1.4 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Robert M. Lavinsky",463,650,{"id":467,"source_url":468,"license_code":433,"credit_html":469,"title":7,"description":11,"author":11,"original_width":470,"original_height":445},30160,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F177378","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F177378\" rel=\"noopener\">Department of Geology, TalTech\u003C\u002Fa> via Europeana",750,{"id":472,"source_url":473,"license_code":433,"credit_html":474,"title":475,"description":476,"author":477,"original_width":478,"original_height":479},15422,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99647992","Ivar Leidus, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99647992\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite - Reocín mine, Cantabria, Spain.jpg","Crystals of marcasite up to 6 mm in size across the matrix (6.0 × 5.0 × 3.0 cm) of crystallized dolomite. Found from Reocín mine, Cantabria, Spain","Ivar Leidus",5250,7000,{"id":481,"source_url":482,"license_code":433,"credit_html":483,"title":7,"description":11,"author":11,"original_width":484,"original_height":445},30161,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F128792","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F128792\" rel=\"noopener\">University of Tartu, Natural History Museum\u003C\u002Fa> via Europeana",676,{"id":486,"source_url":487,"license_code":488,"credit_html":489,"title":490,"description":491,"author":492,"original_width":493,"original_height":494},15423,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594483","CC BY 2.0","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594483\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite nodule (Ohio, USA) 1 - 54102491270.jpg","(crack surface)\n\u003Chr>\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 sulfide minerals contain one or more sulfide anions (S-2).  The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals.  Many sulfides are economically significant, as they occur commonly in ores.  The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc.  Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size.  These minerals will not form in the presence of free oxygen.  Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.\n\u003C\u002Fp>\u003Cp>Marcasite is an iron sulfide mineral, FeS2, which is the same chemical formula as pyrite.  Different minerals having the same chemical formula are called polymorphs.  Other examples of polymorphs are graphite-diamond (both C) and calcite-aragonite (both CaCO3).  Pyrite and marcasite both have a metallic luster, a brassy gold color, and a dark gray to black streak.  They both lack cleavage, and they have the same hardness (H = 6 to 6.5).  Marcasite tends to have a paler brass color than pyrite.  Some marcasites are almost silvery-colored.\n\u003C\u002Fp>\u003Cp>How does one visually distinguish marcasite from pyrite?  Apart from color, marcasite crystals are typically plates, or sharp & pointed, and marcasite tends to twin, resulting in cockscomb masses (www.mindat.org\u002Fphoto-408969.html).  Marcasite also more readily breaks down into whitish powder (FeSO4).\n\u003C\u002Fp>\u003Cp>Pyrite can convert to marcasite naturally, and vice versa.  Pyrite concretions may have preserved needle-shaped crystals of marcasite, but the marcasite is gone.  X-ray analysis may be needed to determine which polymorph is present.\n\u003C\u002Fp>\u003Cp>Stratigraphy: possibly \u002F probably derived from the Ohio Shale (Upper Devonian)\n\u003C\u002Fp>\u003Cp>Locality: central Ohio, USA\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of marcasite:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=2571","James St. John",1896,1945,{"id":496,"source_url":497,"license_code":433,"credit_html":498,"title":7,"description":11,"author":11,"original_width":445,"original_height":470},30162,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F199467","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F199467\" rel=\"noopener\">University of Tartu, Natural History Museum\u003C\u002Fa> via Europeana",{"id":500,"source_url":501,"license_code":488,"credit_html":502,"title":503,"description":491,"author":492,"original_width":504,"original_height":505},15424,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594484","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594484\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite nodule (Ohio, USA) 2 - 54102033446.jpg",1935,2004,{"id":507,"source_url":508,"license_code":433,"credit_html":509,"title":7,"description":11,"author":11,"original_width":445,"original_height":510},30163,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F190736","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F190736\" rel=\"noopener\">University of Tartu, Natural History Museum\u003C\u002Fa> via Europeana",649,{"id":512,"source_url":513,"license_code":488,"credit_html":514,"title":515,"description":516,"author":492,"original_width":517,"original_height":518},15425,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594485","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594485\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite (Vulcan Materials quarry, Racine, Wisconsin, USA).jpg","\"Turkey tail\" marcasite from Wisconsin, 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 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 sulfide minerals contain one or more sulfide anions (S-2).  The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals.  Many sulfides are economically significant, as they occur commonly in ores.  The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc.  Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size.  These minerals will not form in the presence of free oxygen.  Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.\n\u003C\u002Fp>\u003Cp>Marcasite is an iron sulfide mineral, FeS2, which is the same chemical formula as pyrite.  Different minerals having the same chemical formula are called polymorphs.  Other examples of polymorphs are graphite-diamond (both C) and calcite-aragonite (both CaCO3).  Pyrite and marcasite both have a metallic luster, a brassy gold color, and a dark gray to black streak.  They both lack cleavage, and they have the same hardness (H = 6 to 6.5).  Marcasite tends to have a paler brass color than pyrite.  Some marcasites are almost silvery-colored.\n\u003C\u002Fp>\u003Cp>How does one visually distinguish marcasite from pyrite?  Apart from color, marcasite crystals are typically plates, or sharp & pointed, and marcasite tends to twin, resulting in cockscomb masses (www.mindat.org\u002Fphoto-408969.html).  Marcasite also more readily breaks down into whitish powder (FeSO4).\n\u003C\u002Fp>\u003Cp>Pyrite can convert to marcasite naturally, and vice versa.  Pyrite concretions may have preserved needle-shaped crystals of marcasite, but the marcasite is gone.  X-ray analysis may be needed to determine which polymorph is present.\n\u003C\u002Fp>\u003Cp>Locality: Vulcan Materials quarry, Racine, far-southeastern Wisconsin, USA\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of marcasite:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=2571",3783,2435,{"id":520,"source_url":521,"license_code":450,"credit_html":522,"title":523,"description":524,"author":463,"original_width":525,"original_height":526},64914,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145644","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145644\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite-148327.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Rensselaer Quarry (Rensselaer Stone Company Quarry; Pleasant Ridge Quarry), \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FPleasant_Ridge\" class=\"extiw\" title=\"en:Pleasant Ridge\">Pleasant Ridge\u003C\u002Fa>, Jasper County, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FIndiana\" class=\"extiw\" title=\"en:Indiana\">Indiana\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-10676.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 3.8 x 3.3 x 2.0 cm.\u003C\u002Fdd>\n\u003Cdd>A BEAUTIFUL and AESTHETIC, two-sided, fan-like specimen of radiating clusters of lustrous, very sharp and brassy marcasite crystals from the famous Resselaer Quarry of Indiana. Marcasites from this locality are stable and make for great specimens of the species. This well-known quarry is now closed and flooded. MUCH BETTER IN PERSON. Ex. George Feist Collection #3119.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",500,398,{"id":528,"source_url":529,"license_code":488,"credit_html":530,"title":531,"description":491,"author":492,"original_width":532,"original_height":533},15426,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594488","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594488\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite nodule (Ohio, USA) 3 - 54102289963.jpg",2099,872,{"id":535,"source_url":536,"license_code":488,"credit_html":537,"title":538,"description":491,"author":492,"original_width":539,"original_height":540},15427,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594489","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=154594489\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite nodule (Ohio, USA) 4 - 54102289998.jpg",2726,836,{"id":542,"source_url":543,"license_code":450,"credit_html":544,"title":545,"description":546,"author":463,"original_width":547,"original_height":548},64918,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10166715","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10166715\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite-247914.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Roşia Montanã (Verespatak; Vöröspatak; Goldbach), \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-2607.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 4.8 x 3.3 x 2.3 cm.\u003C\u002Fdd>\n\u003Cdd>I have not myself seen such a superb specimen of marcasite from this important, ancient gold mining district. Although known for 2000 years, we only know of specimens from a small period of time in the 1700s to 1800s, mainly. So much was lost. And of what survives, it is no wonder that people saved golds over marcasite. This specimen is a rarity. It has a rich metallic-shimmering look to it, quite different and more elegant than marcasite from France or Trepca to my eye. Ex. Harold Urish Collection.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",400,351,{"id":550,"source_url":551,"license_code":433,"credit_html":552,"title":553,"description":554,"author":555,"original_width":556,"original_height":557},64921,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113749598","Koreller, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113749598\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Muséum de Nantes - 515 - Marcasite.jpg","Marcasite, au Muséum de Nantes","Koreller",4272,2848,{"id":559,"source_url":560,"license_code":433,"credit_html":561,"title":562,"description":563,"author":555,"original_width":564,"original_height":565},64922,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113749627","Koreller, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113749627\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Muséum de Nantes - 530 - Marcasite (États-Unis).jpg","Marcasite, en provenance des États-Unis, au Muséum de Nantes",3184,2304,{"id":567,"source_url":568,"license_code":433,"credit_html":569,"title":570,"description":563,"author":555,"original_width":571,"original_height":572},64923,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113749631","Koreller, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113749631\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Muséum de Nantes - 531 - Marcasite (États-Unis).jpg",2992,2168,{"id":574,"source_url":575,"license_code":443,"credit_html":576,"title":577,"description":578,"author":579,"original_width":580,"original_height":581},64925,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=141680586","Klaproth, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=141680586\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite Kühlungsborn Germany.jpg","Massive aggregate (app. 9 x 7 x 5.5 cm) of marcasite from the steep coast near Kühlungsborn, Mecklenburg-West Pomerania, Germany","Klaproth",3965,2294,{"id":583,"source_url":584,"license_code":450,"credit_html":585,"title":586,"description":587,"author":463,"original_width":588,"original_height":589},64912,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10136104","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10136104\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Pyrite-Marcasite-Calcite-61202.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FPyrite\" class=\"extiw\" title=\"en:Pyrite\">Pyrite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCalcite\" class=\"extiw\" title=\"en:Calcite\">Calcite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FDolomite\" class=\"extiw\" title=\"en:Dolomite\">Dolomite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FQuartz\" class=\"extiw\" title=\"en:Quartz\">Quartz\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNanisivik_Mine\" class=\"extiw\" title=\"en:Nanisivik Mine\">Nanisivik Mine\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNanisivik\" class=\"extiw\" title=\"en:Nanisivik\">Nanisivik\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FBaffin_Island\" class=\"extiw\" title=\"en:Baffin Island\">Baffin Island\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNunavut\" class=\"extiw\" title=\"en:Nunavut\">Nunavut Territory\u003C\u002Fa>, Canada (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-514.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>A DRAMATIC and SIGNIFICANT LARGE CABINET combination piece from the famous Nanisivik Mine, above the Arctic Circle on Baffin Island, North West Territory, Canada. Most of the specimen and matrix consists of sparkly, brassy pyrite blades pseudomorphing marcasite. Aesthetically scattered are lustrous, doubly terminated, amber calcite crystals to 1.8 cm, clusters of lustrous, chalcopyrite-speckled, gray dolomite rhombs, and transparent, water-clear, doubly terminated quartz crystals to 5.8 cm. Scattered periphery damage is trivial, for such a large piece. The Nanisivik Mine is one of the highest latitude and coldest underground mines in the world. 15.3 x 11.5 x 7.0 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",556,675,{"id":591,"source_url":592,"license_code":450,"credit_html":593,"title":594,"description":595,"author":463,"original_width":547,"original_height":596},64913,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145590","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10145590\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Galena-Sphalerite-Marcasite-148274.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGalena\" class=\"extiw\" title=\"en:Galena\">Galena\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSphalerite\" class=\"extiw\" title=\"en:Sphalerite\">Sphalerite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Barr Mine, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FVinegar_Hill\" class=\"extiw\" title=\"en:Vinegar Hill\">Vinegar Hill\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTreece\" class=\"extiw\" title=\"en:Treece\">Treece\u003C\u002Fa>, Picher Field, Tri-State District, Cherokee County, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FKansas\" class=\"extiw\" title=\"en:Kansas\">Kansas\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-8570.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 13.4 x 12.4 x 7.1 cm.\u003C\u002Fdd>\n\u003Cdd>An old label cut from a larger list says \"from Barr Mine, Treece, Kansas, Boodle Lane, November 6, 1937\". So this large and impressive old Tri-State specimen has a very specific date and locality to it! It consists of sharp cubes of galena on a glittering mass of microcrystalline, deep red sphalerite (the maroon color shows up under strong light), with minor associated marcasite. It seems to have formed as a thick knob around dolomite which you can now see in the center of the underside of the specimen.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",321,{"id":598,"source_url":599,"license_code":450,"credit_html":600,"title":601,"description":602,"author":463,"original_width":603,"original_height":604},64915,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10147875","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10147875\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite-Galena-Sphalerite-162485.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGalena\" class=\"extiw\" title=\"en:Galena\">Galena\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSphalerite\" class=\"extiw\" title=\"en:Sphalerite\">Sphalerite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOlkusz\" class=\"extiw\" title=\"en:Olkusz\">Olkusz\u003C\u002Fa>, Olkusz District, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FLesser_Poland_Voivodeship\" class=\"extiw\" title=\"en:Lesser Poland Voivodeship\">Małopolskie\u003C\u002Fa>, Poland (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-131442.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 22.5 x 15.3 x 1.2 cm.\u003C\u002Fdd>\n\u003Cdd>This is a large, striking slab of banded minerals from Poland we acquired from the collection of Dave Stoudt, who was stationed in Poland for a decade and was able to buy from miners and dealers during his time there. It is a slice through essentially a boulder of alternating bands of three different minerals that were laid down in successive layers, similar to the way agate gets its bands, but with an exotic mix of minerals here rather than just quartz (as with agate).\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",600,379,{"id":606,"source_url":607,"license_code":450,"credit_html":608,"title":609,"description":610,"author":463,"original_width":603,"original_height":611},64916,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10163306","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10163306\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Calcite-Marcasite-228329.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCalcite\" class=\"extiw\" title=\"en:Calcite\">Calcite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Sweetwater Mine (Milliken Mine; Frank R. Milliken; Blair Creek; Ozark Lead Company Mine; Adair Creek; Logan Creek), \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FEllington\" class=\"extiw\" title=\"en:Ellington\">Ellington\u003C\u002Fa>, Viburnum Trend District, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FReynolds_County,_Missouri\" class=\"extiw\" title=\"en:Reynolds County, Missouri\">Reynolds County\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMissouri\" class=\"extiw\" title=\"en:Missouri\">Missouri\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-3866.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 8.9 x 5.9 x 3.6 cm.\u003C\u002Fdd>\n\u003Cdd>An excellent and showy combination specimen from the Sweetwater Mine of Missouri’s Viburnum Trend. Gemmy, mostly transparent, singly and doubly terminated, light amber calcite crystals are richly and aesthetically scattered on the upright matrix of brassy marcasite crystals. The calcite crystals are up to 2.0 cm long. Ex. George Feist Collection.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",457,{"id":613,"source_url":614,"license_code":450,"credit_html":615,"title":616,"description":617,"author":463,"original_width":618,"original_height":603},64917,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10165882","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10165882\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Galena-Dolomite-Marcasite-243358.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGalena\" class=\"extiw\" title=\"en:Galena\">Galena\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FDolomite\" class=\"extiw\" title=\"en:Dolomite\">Dolomite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\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: Buick Mine (Amax Buick Mine; Moloc Mine), \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FBixby\" class=\"extiw\" title=\"en:Bixby\">Bixby\u003C\u002Fa>, Viburnum Trend District, Iron County, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMissouri\" class=\"extiw\" title=\"en:Missouri\">Missouri\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-3871.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 7.2 x 4.6 x 2.5 cm.\u003C\u002Fdd>\n\u003Cdd>A rare and superb cluster of sharp, highly to moderately lustrous, lead-gray, parallel-growth, spinel-twinned galena crystals from the Buick Mine of Missouri’s Viburnum Trend. These large crystals and style are classic for a particular find there, in the 1990s. This excellent, complete-all-around crystal is richly and beautifully covered on the back and one edge with lustrous dolomite rhombs, sparkly, brassy marcasite crystals and a couple of well-placed, calcite scalenohedrons. The doubly terminated calcite on the end is 1.5 cm (one end is cleaved).\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",581,{"id":620,"source_url":621,"license_code":433,"credit_html":622,"title":623,"description":624,"author":625,"original_width":626,"original_height":627},64924,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=132197806","Mineralysk, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=132197806\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","1157 Markazit a pyrit - Bankov - Košice.jpg","1157 Markazit a pyrit - Bankov - Košice","Mineralysk",1368,800,{"id":629,"source_url":630,"license_code":443,"credit_html":631,"title":632,"description":633,"author":634,"original_width":635,"original_height":636},64926,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146588358","Slashme, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=146588358\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Markasit Calcit.jpg","Marcasite and calcite from Becke-Oese quarry, Hemer, Sauerland, Germany","Slashme",4953,2750,{"id":638,"source_url":639,"license_code":433,"credit_html":640,"title":641,"description":642,"author":643,"original_width":644,"original_height":645},64927,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=179299462","Ethmostigmus, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=179299462\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Calcite (calcium carbonate) with marcasite at Melbourne Museum.jpg","A specimen of calcite (calcium carbonate) with marcasite on display at Melbourne Museum in Victoria, Australia. This specimen was sourced from Brushy Creek Mine in Missouri, United States.","Ethmostigmus",4615,3076,{"id":647,"source_url":648,"license_code":649,"credit_html":650,"title":651,"description":652,"author":653,"original_width":654,"original_height":655},15221,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118204964","CC BY-SA 2.0","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>","Pacific Museum of Earth from Canada",4000,6000,{"id":657,"source_url":658,"license_code":649,"credit_html":659,"title":660,"description":661,"author":653,"original_width":655,"original_height":654},27501,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118206484","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118206484\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Marcasite with Pyrrhotite, Chalcopyrite, and Violarite (40945032473).jpg","Falconbridge, Ontario, Canada - S-74-1778",{"id":663,"source_url":664,"license_code":433,"credit_html":665,"title":666,"description":11,"author":11,"original_width":667,"original_height":668},29029,"https:\u002F\u002Fclasate.cimec.ro\u002Fdetaliu.asp?k=ba55b57f98954181a5efc305faf537b9","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fclasate.cimec.ro\u002Fdetaliu.asp?k=ba55b57f98954181a5efc305faf537b9\" rel=\"noopener\">Argeș County Museum\u003C\u002Fa> via Europeana","marcasită, calcit",1200,900,{"id":670,"source_url":671,"license_code":450,"credit_html":672,"title":673,"description":674,"author":463,"original_width":675,"original_height":676},61408,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10168263","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10168263\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Ferberite-Marcasite-Jamesonite-255171.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FFerberite\" class=\"extiw\" title=\"en:Ferberite\">Ferberite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMarcasite\" class=\"extiw\" title=\"en:Marcasite\">Marcasite\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FJamesonite\" class=\"extiw\" title=\"en:Jamesonite\">Jamesonite\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Tazna Mine (Tasna Mine; Tazna-Rosario Mine), Cerro Tazna, Atocha-Quechisla District, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNor_Chichas_Province\" class=\"extiw\" title=\"en:Nor Chichas Province\">Nor Chichas Province\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FPotos%C3%AD_Department\" class=\"extiw\" title=\"en:Potosí Department\">Potosí Department\u003C\u002Fa>, Bolivia (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-40745.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 4.6 x 3.8 x 3.6 cm.\u003C\u002Fdd>\n\u003Cdd>A superb twinned crystal of Ferberite from the renowned Tasna mine in southern Bolivia. The piece was mined at the beginning of 2008, which is encouraging because I have seen very little in the way of Ferberites from this mine in recent years. This piece features the classic, \"butterfly\" twinning of Ferberite along the a (100) face. It is a good quality, sharp, lustrous, aesthetic jet-black twinned crystal with associated botryoidal Marcasite and small acicular crystals of grey Jamesonite. It has an attractive thick blocky form, and is a wonderful miniature size specimen. Twinned crystals from Bolivia are becoming increasingly difficult to obtain in recent years as the price of Tungsten ore has driven the miners to throw nearly all the Ferberite into the crusher, causing thousands of specimens to be lost forever.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",477,432,[678,685,690,694],{"id":679,"url":680,"label":681,"formula":682,"spacegroup":683,"year":684},8479,"\u002Fcif\u002F8479.cif","Rieder 2007 · Fe S2","Fe S2","P n n m",2007,{"id":686,"url":687,"label":688,"formula":689,"spacegroup":683,"year":684},8480,"\u002Fcif\u002F8480.cif","Rieder 2007 · Fe (S1.6 As.4)","Fe (S1.6 As.4)",{"id":691,"url":692,"label":693,"formula":682,"spacegroup":683,"year":308},8481,"\u002Fcif\u002F8481.cif","Buerger 1937",{"id":695,"url":696,"label":697,"formula":682,"spacegroup":698,"year":295},8482,"\u002Fcif\u002F8482.cif","Buerger 1931","P m n n",[700,701,702,703,704,705,706,707,708,709,710,711,712,713,714,715,716,717,718,719,720,721,722,723,724,725,726,727],"Alasanit","Alasanita","Alasanite","Alazanit","Alazanita","Alazanite","Binarit","Binarita","Binarite","Binärkies","Hydropyrit","Hydropyrita","Hydropyrite","Kammkies","Lamellar pyrite","Lebererz (of Agricola)","Markasite","Maxy","Pirita Blanca","Poliopyrites","Prismatic Iron Pyrites","Radiated Pyrites","Spear Pyrites","Speerkies","Sperchise","Strahlkies","Weicheisenkies","Weisserkies",[729,733,737,741,745,749,754,758,762,768,772,777,781,785,800,804,809,812,816,820,824,828,832,836,839,843,846,850,854,858,861,865,869,873,877,881,885,888,891,894,897,901,905,909,912,915,919,922,925],{"lang":730,"names":731},"af",[732],"Markasiet",{"lang":734,"names":735},"ar",[736],"مرقشيت",{"lang":738,"names":739},"az",[740],"Markazit",{"lang":742,"names":743},"be",[744],"Марказіт",{"lang":746,"names":747},"ca",[748],"marcassita",{"lang":750,"names":751},"cs",[752,753],"kyz kopinatý","markazit",{"lang":755,"names":756},"de",[757],"Markasit",{"lang":759,"names":760},"el",[761],"Μαρκασίτης",{"lang":763,"names":764},"es",[765,766,767],"marcasita","margajita","nicoya",{"lang":769,"names":770},"et",[771],"markasiit",{"lang":773,"names":774},"eu",[775,776],"Marcasita","Markasita",{"lang":778,"names":779},"fa",[780],"مارکارسیت",{"lang":782,"names":783},"fi",[784],"markasiitti",{"lang":786,"names":787},"fr",[702,708,788,789,712,790,791,792,7,793,794,719,795,796,797,798,799],"Binarkies","Cyrosite","Kausimkies","Kyrosite","Lonchandite","marcassite","Métalonchidite","Pyrite blanche","Pyrite crêtée","Pyrite lamelleuse","Pyrite rhomboïdale","Sperkise",{"lang":801,"names":802},"ga",[803],"marcaisít",{"lang":805,"names":806},"he",[807,808],"מרכזיט","מרקזיט",{"lang":810,"names":811},"hu",[740],{"lang":813,"names":814},"hy",[815],"Մարկազիտ",{"lang":817,"names":818},"it",[819],"marcasite",{"lang":821,"names":822},"ja",[823],"白鉄鉱",{"lang":825,"names":826},"ka",[827],"მარკაზიტი",{"lang":829,"names":830},"kk",[831],"Марказит",{"lang":833,"names":834},"ko",[835],"마카사이트",{"lang":837,"names":838},"ky",[831],{"lang":840,"names":841},"lt",[842],"Markazitas",{"lang":844,"names":845},"mg",[776],{"lang":847,"names":848},"mk",[849],"марказит",{"lang":851,"names":852},"nb",[853],"markasitt",{"lang":855,"names":856},"nl",[857,732,723],"marcasiet",{"lang":859,"names":860},"nn",[853],{"lang":862,"names":863},"no",[864],"Markasitt",{"lang":866,"names":867},"oc",[868],"Marcassita",{"lang":870,"names":871},"pl",[872],"Markasyt",{"lang":874,"names":875},"pt",[748,876],"Marcassite",{"lang":878,"names":879},"ro",[880],"marcasită",{"lang":882,"names":883},"ru",[884,831],"Лучистый колчедан",{"lang":886,"names":887},"sk",[740],{"lang":889,"names":890},"sl",[753],{"lang":892,"names":893},"sv",[757],{"lang":895,"names":896},"uk",[831],{"lang":898,"names":899},"uz",[740,900],"Nursimon kolchedan",{"lang":902,"names":903},"vi",[904],"Marcasit",{"lang":906,"names":907},"zh",[908],"白铁矿",{"lang":910,"names":911},"zh-cn",[908],{"lang":913,"names":914},"zh-hans",[908],{"lang":916,"names":917},"zh-hant",[918],"白鐵礦",{"lang":920,"names":921},"zh-hk",[918],{"lang":923,"names":924},"zh-sg",[908],{"lang":926,"names":927},"zh-tw",[918],"Q409087",{"history":930,"applications":934},{"markdown":931,"model_version":932,"prompt_version":933,"reviewed_at":11},"For most of its written life, the word **marcasite** did not mean what it means now. It was a catch-all for any pale brassy iron sulfide a miner dug out of the ground. The modern, narrower definition arrived late — only in 1845[1].\n\nThe word itself comes from Arabic. In medieval and early-modern Europe, it was applied indiscriminately to pyrite and other metallic bronze-coloured minerals[2]. Pyrite and marcasite were, for most readers and writers of the time, the same thing under different lights.\n\nThe confusion runs through the surviving sources. In 1665, Walter Pope described \"marcasites\" in the mercury ores of the Idria Mine, in the Julian Alps of what is now Slovenia[3]. The mine did contain both minerals — metallic golden specks of marcasite alongside golden pyrite — but Pope had no way to tell them apart. Over a century later, in 1771, Johnathan Hill was still using *marcasite* as a loose term for any massive *pyrites* or *mundic*[4].\n\nThe split came from Wilhelm Karl von Haidinger, who in 1845 fixed *marcasite* to one specific mineral: the orthorhombic polymorph of iron disulfide (FeS₂)[1]. *Orthorhombic* means built on three perpendicular axes of unequal length — a different scaffold from pyrite's cube. Same atoms, different shape.\n\nThe old meaning never quite died. The Victorian and Edwardian fashion for *marcasite jewellery* — small faceted stones set in mourning brooches and rings — predates Haidinger's definition[5]. It uses the older sense of the word: the pale brassy gems in those pieces are almost always pyrite. True marcasite is too brittle to cut and too unstable to wear. Specimens in mineral cabinets are notorious for falling apart over time. The sulfur oxidises in damp air and combines with water to produce iron sulfate and sulfuric acid[6].","claude-opus-4-7","1.7.0",{"markdown":935,"model_version":932,"prompt_version":933,"reviewed_at":11},"Marcasite has no significant industrial use today. The same instability that makes specimens crumble in mineral cabinets rules it out of any application that requires it to last. In moist air, the sulfur oxidises and combines with water to produce iron sulfate and sulfuric acid. Storage below 60 percent humidity slows the reaction but does not stop it[1].\n\nWhere pyrite, its cubic cousin with the same FeS₂ formula, finds a handful of niche uses, marcasite stays on the shelf. Demand comes from mineral collectors and museums, drawn to the distinctive cockscomb and spear-shaped crystal habits marcasite produces[2]."]