[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"minerals:one:1136":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":11,"strunz10ed1":25,"strunz10ed2":26,"strunz10ed3":27,"strunz10ed4":28,"dana8ed1":25,"dana8ed2":29,"dana8ed3":30,"dana8ed4":30,"csystem":31,"cclass":32,"spacegroup":33,"spacegroupset":34,"a":35,"b":34,"c":36,"alpha":34,"beta":34,"gamma":34,"aerror":11,"berror":11,"cerror":11,"alphaerror":11,"betaerror":11,"gammaerror":11,"va3":37,"z":38,"csmetamict":14,"commentcrystal":11,"twinning":39,"tranglide":11,"parting":40,"epitaxidescription":11,"morphology":41,"tlform":11,"hmin":42,"hmax":42,"hardtype":43,"vhnmin":34,"vhnmax":34,"vhnerror":11,"vhng":11,"vhns":11,"commenthard":11,"dmeas":44,"dmeas2":45,"dcalc":46,"dmeaserror":11,"dcalcerror":11,"commentdense":11,"lustre":11,"lustretype":47,"commentluster":11,"diapheny":48,"streak":49,"colour":50,"commentcolor":11,"colors":51,"streak_colors":60,"luminescence":11,"uv":11,"cleavage":11,"cleavagetype":61,"fracturetype":62,"tenacity":63,"commentbreak":11,"opticaltype":64,"opticalsign":65,"opticalalpha":34,"opticalalpha2":34,"opticalalphaerror":11,"opticalbeta":34,"opticalbeta2":34,"opticalbetaerror":11,"opticalgamma":34,"opticalgamma2":34,"opticalgammaerror":11,"opticalomega":66,"opticalomega2":67,"opticalomegaerror":11,"opticalepsilon":68,"opticalepsilon2":69,"opticalepsilonerror":11,"opticaln":34,"opticaln2":34,"opticalnerror":11,"optical2vcalc":34,"optical2vcalc2":34,"optical2vcalcerror":11,"optical2vmeasured":70,"optical2vmeasured2":34,"optical2vmeasurederror":11,"rimin":71,"rimax":72,"opticaldispersion":11,"opticalpleochroism":73,"opticalpleochorismdesc":74,"opticalbirefringence":75,"opticalcomments":76,"opticalcolour":77,"opticalinternal":11,"opticaltropic":11,"opticalanisotropism":11,"opticalbireflectance":11,"opticalextinction":11,"opticalr":11,"specdispm":11,"ir":11,"electrical":11,"magnetism":11,"thermalbehaviour":78,"other":79,"industrial":80,"occurrence":11,"otheroccurrence":81,"type_specimen_store":11,"description_short":82,"aboutname":83,"rock_parent":11,"rock_parent2":11,"rock_root":9,"rock_bgs_code":11,"meteoritical_code":11,"updttime":84,"reviewed_at":11,"variety_of":11,"varieties":85,"group_members":98,"associates":128,"confused_with":225,"type_localities":231,"occurrence_total":232,"citations":233,"images":381,"structures":614,"synonyms":641,"language_names":679,"wikidata_qid":1020,"texts":1021},1136,"1:1:1136:1","96dfb345-a230-4fb2-a2ba-f50c48aa5c2c","Corundum","Crn",0,"mineral",null,29296,12831,false,"Al\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>",[17,18],"Al","O",[17,18],"Cr, Fe, V, Ti","7.6.1",[23,24],"APPROVED","GRANDFATHERED","4","C","B","05","3","1","Trigonal",13,98,"0","4.75","12.982",253.54,6,"\u003Cmi>1. Common {101_1}; usually lamellar, producing a lamellar structure and striae on c and r. Less commonly penetration twins or arrowhead twins with crystals tabular {112_0}. 2. On {0001}, less common. Pressure twinning produced on {101_1}, and on {0001}.\u003C\u002Fmi>","Rhombohedral and basal parting {0001}, sometimes perfect but interrupted; also on \u003Cmi>{101_1}\u003C\u002Fmi> due to exsolution (Boehmite), observed on large blocks (Georgia, USA).","Often steep pyramidal on w, z, E, or ω. Barrel-shaped crystals that are often rough and rounded, of considerable size at times, varying from short prismatic [0001] with a large base to steep pyramidal. Less commonly, flat tabular {0001} or rhombohedral. Striae on {0001} parallel \u003Cmi>[01_10]\u003C\u002Fmi>. Lines in the direction \u003Cmi>[11_20]\u003C\u002Fmi> divide the base into six sectors at times.\r\n\r\nForms include \u003Cmi>{0001}, {1000}, {11_20}, {71_80}, {10_15}, {10_13}, {10_12}, {10_11}, {70_72}, {70_71}, {01_11}, {02_21}, {07_72}, {22_45}, {22_43}, {7·7·_14·9}, {11_21}, {7·7·_14·6}, {44_88}, {11·11·_22·6}, {22_41}, {7·7·_14·3}, {8·8·_16·3}, {44_81}, {14·14·_28·3}, {42_65}, {32_54}, {2·8·_10·9}\u003C\u002Fmi>",9,4,"3.98","4.1","3.997","Adamantine,Vitreous,Pearly","Transparent,Translucent,Opaque","White","Colourless, blue, red, pink, yellow, grey, golden-brown",[52,53,54,55,56,57,58,59],"colorless","blue","red","pink","yellow","gray","brown","white",[59],"None Observed","Irregular\u002FUneven,Conchoidal","brittle","Uniaxial","-","1.767","1.772","1.759","1.763","58",1.759,1.772,"Not Visible","Weak in sapphire (e = blue-green to yellow-green, o = pale to deep blue), otherwise none visible.","Low, first-order greys and whites.","Asterism often present due to oriented needle-like inclusions or to colloidal or other material deposited in oriented tubules.","Colourless","Before the blowpipe, unaltered.","Not affected by acids.","Corundum is used as an abrasive (\"Emery\"), and the gem varieties of corundum are better-known as Ruby and Sapphire.","Silica-poor rocks, such as Nepheline-Syenites, alkali igneous undersaturated rocks, contact aureoles in altered aluminous shales, aluminous xenoliths in high temperature plutonic and hypabyssal rocks, metamorphosed bauxite deposits, and as a detrital material in sediments.","The aluminum analogue of Eskolaite, Hematite, and Karelianite. \r\nThe red (Cr-bearing) gem variety is called Ruby. \r\nThe blue (Fe- and Ti-bearing) gem variety is called Sapphire.\r\n\r\nCompare 'silicon spinel', that might be similar to the gamma form of Al...","Named \"corinvindum\" in 1725 by John Woodward and derived from the Sanskrit, kuruvinda (\"Ruby\"). Richard Kirwan used the current spelling \"corundum\" in 1794. Known by many names in ancient times: adamant, sapphire, ruby, hyacinthos, asteria, etc.","2026-03-18 17:22:01",[86,91,95],{"id":87,"name":88,"entrytype":89,"csystem":31,"ima_formula":11,"mindat_formula":15,"hmin":42,"hmax":42,"dmeas":34,"dcalc":34,"primary_image_id":90},3473,"Ruby",2,77550,{"id":92,"name":93,"entrytype":89,"csystem":11,"ima_formula":11,"mindat_formula":15,"hmin":11,"hmax":11,"dmeas":34,"dcalc":34,"primary_image_id":94},3529,"Sapphire",72351,{"id":96,"name":97,"entrytype":89,"csystem":11,"ima_formula":11,"mindat_formula":15,"hmin":11,"hmax":11,"dmeas":34,"dcalc":34,"primary_image_id":11},30578,"Star Corundum",[99,108,116,123],{"id":100,"name":101,"entrytype":9,"csystem":31,"ima_formula":102,"mindat_formula":102,"hmin":103,"hmax":104,"dmeas":105,"dcalc":106,"primary_image_id":107},1411,"Eskolaite","Cr\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>",8,8.5,"5.18","5.20",8069,{"id":109,"name":110,"entrytype":9,"csystem":31,"ima_formula":111,"mindat_formula":111,"hmin":112,"hmax":38,"dmeas":113,"dcalc":114,"primary_image_id":115},1856,"Hematite","Fe\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>",5,"5.26","5.255",29858,{"id":117,"name":118,"entrytype":9,"csystem":31,"ima_formula":119,"mindat_formula":120,"hmin":103,"hmax":42,"dmeas":34,"dcalc":121,"primary_image_id":122},2158,"Karelianite","V\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>","V\u003Csup>3+\u003C\u002Fsup>\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>","4.95",12973,{"id":124,"name":125,"entrytype":9,"csystem":31,"ima_formula":126,"mindat_formula":127,"hmin":11,"hmax":11,"dmeas":11,"dcalc":11,"primary_image_id":11},38695,"Tistarite","Ti\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>","Ti\u003Csup>3+\u003C\u002Fsup>\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>",[129,137,147,155,163,171,176,184,193,203,208,214,221],{"id":130,"name":131,"entrytype":9,"csystem":132,"ima_formula":133,"mindat_formula":133,"hmin":112,"hmax":38,"dmeas":134,"dcalc":135,"primary_image_id":136},39,"Aeschynite-(Y)","Orthorhombic","Y(TiNb)O\u003Csub>6\u003C\u002Fsub>","4.82","5.5",296,{"id":138,"name":139,"entrytype":9,"csystem":132,"ima_formula":140,"mindat_formula":141,"hmin":142,"hmax":143,"dmeas":144,"dcalc":145,"primary_image_id":146},217,"Andalusite","Al\u003Csub>2\u003C\u002Fsub>SiO\u003Csub>5\u003C\u002Fsub>","Al\u003Csub>2\u003C\u002Fsub>(SiO\u003Csub>4\u003C\u002Fsub>)O",6.5,7.5,"3.13","3.149",29089,{"id":148,"name":149,"entrytype":9,"csystem":132,"ima_formula":150,"mindat_formula":150,"hmin":151,"hmax":143,"dmeas":152,"dcalc":153,"primary_image_id":154},1128,"Cordierite","Mg\u003Csub>2\u003C\u002Fsub>Al\u003Csub>4\u003C\u002Fsub>Si\u003Csub>5\u003C\u002Fsub>O\u003Csub>18\u003C\u002Fsub>",7,"2.6","2.505",6260,{"id":156,"name":157,"entrytype":9,"csystem":132,"ima_formula":158,"mindat_formula":159,"hmin":143,"hmax":143,"dmeas":160,"dcalc":161,"primary_image_id":162},1737,"Grandidierite","MgAl\u003Csub>3\u003C\u002Fsub>O\u003Csub>2\u003C\u002Fsub>(BO\u003Csub>3\u003C\u002Fsub>)(SiO\u003Csub>4\u003C\u002Fsub>)","(Mg,Fe\u003Csup>2+\u003C\u002Fsup>)(Al,Fe\u003Csup>3+\u003C\u002Fsup>)\u003Csub>3\u003C\u002Fsub>(SiO\u003Csub>4\u003C\u002Fsub>)(BO\u003Csub>3\u003C\u002Fsub>)O\u003Csub>2\u003C\u002Fsub>","2.98","3.00",10338,{"id":164,"name":165,"entrytype":9,"csystem":166,"ima_formula":167,"mindat_formula":167,"hmin":143,"hmax":103,"dmeas":168,"dcalc":169,"primary_image_id":170},1897,"Hibonite","Hexagonal","CaAl\u003Csub>12\u003C\u002Fsub>O\u003Csub>19\u003C\u002Fsub>","3.83","4.09",11379,{"id":172,"name":173,"entrytype":9,"csystem":174,"ima_formula":175,"mindat_formula":175,"hmin":11,"hmax":11,"dmeas":11,"dcalc":11,"primary_image_id":11},40647,"Icosahedrite","Icosahedral","Al\u003Csub>63\u003C\u002Fsub>Cu\u003Csub>24\u003C\u002Fsub>Fe\u003Csub>13\u003C\u002Fsub>",{"id":177,"name":178,"entrytype":9,"csystem":132,"ima_formula":179,"mindat_formula":180,"hmin":38,"hmax":151,"dmeas":181,"dcalc":182,"primary_image_id":183},2254,"Kornerupine","(Mg,Fe\u003Csup>2+\u003C\u002Fsup>,Al,◻)\u003Csub>10\u003C\u002Fsub>(Si,Al,B)\u003Csub>5\u003C\u002Fsub>O\u003Csub>21\u003C\u002Fsub>(OH,F)\u003Csub>2\u003C\u002Fsub>","Mg\u003Csub>3\u003C\u002Fsub>Al\u003Csub>6\u003C\u002Fsub>(Si,Al,B)\u003Csub>5\u003C\u002Fsub>O\u003Csub>21\u003C\u002Fsub>(OH)","3.29","3.288",13557,{"id":185,"name":186,"entrytype":9,"csystem":187,"ima_formula":188,"mindat_formula":188,"hmin":189,"hmax":38,"dmeas":190,"dcalc":191,"primary_image_id":192},2356,"Lazulite","Monoclinic","MgAl\u003Csub>2\u003C\u002Fsub>(PO\u003Csub>4\u003C\u002Fsub>)\u003Csub>2\u003C\u002Fsub>(OH)\u003Csub>2\u003C\u002Fsub>",5.5,"3.122","3.144",14167,{"id":194,"name":195,"entrytype":9,"csystem":187,"ima_formula":196,"mindat_formula":197,"hmin":198,"hmax":199,"dmeas":200,"dcalc":201,"primary_image_id":202},2573,"Margarite","CaAl\u003Csub>2\u003C\u002Fsub>Si\u003Csub>2\u003C\u002Fsub>Al\u003Csub>2\u003C\u002Fsub>O\u003Csub>10\u003C\u002Fsub>(OH)\u003Csub>2\u003C\u002Fsub>","CaAl\u003Csub>2\u003C\u002Fsub>(Al\u003Csub>2\u003C\u002Fsub>Si\u003Csub>2\u003C\u002Fsub>O\u003Csub>10\u003C\u002Fsub>)(OH)\u003Csub>2\u003C\u002Fsub>",3.5,4.5,"2.99","3.077",15433,{"id":204,"name":205,"entrytype":9,"csystem":206,"ima_formula":207,"mindat_formula":207,"hmin":104,"hmax":104,"dmeas":34,"dcalc":34,"primary_image_id":11},3035,"Osbornite","Isometric","TiN",{"id":209,"name":210,"entrytype":9,"csystem":211,"ima_formula":212,"mindat_formula":212,"hmin":112,"hmax":112,"dmeas":34,"dcalc":213,"primary_image_id":11},7251,"Pretulite","Tetragonal","Sc(PO\u003Csub>4\u003C\u002Fsub>)","3.71",{"id":215,"name":216,"entrytype":9,"csystem":187,"ima_formula":217,"mindat_formula":217,"hmin":38,"hmax":38,"dmeas":218,"dcalc":219,"primary_image_id":220},3596,"Scorzalite","Fe\u003Csup>2+\u003C\u002Fsup>Al\u003Csub>2\u003C\u002Fsub>(PO\u003Csub>4\u003C\u002Fsub>)\u003Csub>2\u003C\u002Fsub>(OH)\u003Csub>2\u003C\u002Fsub>","3.33","3.32",21923,{"id":222,"name":223,"entrytype":89,"csystem":11,"ima_formula":11,"mindat_formula":224,"hmin":11,"hmax":11,"dmeas":34,"dcalc":34,"primary_image_id":11},27165,"Star Garnet","Fe\u003Csup>2+\u003C\u002Fsup>\u003Csub>3\u003C\u002Fsub>Al\u003Csub>2\u003C\u002Fsub>(SiO\u003Csub>4\u003C\u002Fsub>)\u003Csub>3\u003C\u002Fsub>",[226],{"id":227,"name":228,"entrytype":9,"csystem":211,"ima_formula":229,"mindat_formula":229,"hmin":11,"hmax":11,"dmeas":11,"dcalc":230,"primary_image_id":11},47933,"Deltalumite","(Al\u003Csub>0.67\u003C\u002Fsub>◻\u003Csub>0.33\u003C\u002Fsub>)Al\u003Csub>2\u003C\u002Fsub>O\u003Csub>4\u003C\u002Fsub>","3.663",[],1601,[234,237,241,245,249,253,258,262,266,271,276,280,285,290,294,298,303,307,311,315,320,323,328,332,336,340,344,348,352,356,360,363,366,371,376],{"id":235,"year":11,"html":236,"doi":11},17436983,"Pignatelli, I., Nespolo, M., Pardieu, V., Giuliani, G., Morlot, C. (2024): Basal twinning of Greenland. Mineralogy and Petrology, 118, (in press).",{"id":238,"year":239,"html":240,"doi":11},16104246,1565,"Gesner, C. (1565) Gemmis, quae erant in veste Aaronis, Liber Graecus, & e regione Latinus, Iola Hierotarantino interprete: cum Corollario Conradi Gesneri. in Sancti Patris Epiphanii Episcopi Cypri ad Diodorum Tyri episcopum, De XII, 1-29.",{"id":242,"year":243,"html":244,"doi":11},16106613,1805,"Haüy (1805): Ann. Phys.: 20: 187.",{"id":246,"year":247,"html":248,"doi":11},16106614,1806,"Lucas (1806): 1: 257.",{"id":250,"year":251,"html":252,"doi":11},16106615,1891,"Edmond Frémy (1891): Synthèse du rubis. Vve. Ch. Dunod, France. [https:\u002F\u002Farchive.org\u002Fdetails\u002FSyntheseDuRubis]",{"id":254,"year":255,"html":256,"doi":257},4530,1895,"Judd, John W. (1895) On the Structure-Planes of Corundum. \u003Ci>Mineralogical Magazine and Journal of the Mineralogical Society\u003C\u002Fi>,  11 (50) 49-55 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1180\u002Fminmag.1895.011.50.01'>doi:10.1180\u002Fminmag.1895.011.50.01\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002FMinMag\u002FVolume_11\u002F11-50-49.pdf' class='refpdflink'>\u003C\u002Fa>","10.1180\u002Fminmag.1895.011.50.01",{"id":259,"year":260,"html":261,"doi":11},16106617,1906,"Pratt, J.H. (1906) Corundum and its occurrence and distribution in the United States. United States Geological Survey, Bulletin 269: 175 pgs.",{"id":263,"year":264,"html":265,"doi":11},16106618,1910,"Goldschmidt, V., Schroeder, R. (1910) Über Korund. Zeitschrift für Kristallographie, Mineralogie und Petrographie, Abt. B, Mineralogische und petrographische Mitteilungen: 29(6): 461-488.",{"id":267,"year":268,"html":269,"doi":270},1184073,1925,"Pauling, Linus, Hendricks, Sterling B. (1925) The crystal structures of hematite and corundum. \u003Ci>Journal Of The American Chemical Society\u003C\u002Fi>,  47 (3). 781-790 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1021\u002Fja01680a027'>doi:10.1021\u002Fja01680a027\u003C\u002Fa>","10.1021\u002Fja01680a027",{"id":272,"year":273,"html":274,"doi":275},7047,1927,"Spencer, L. J. (1927) Corundum twins from Transvaal. \u003Ci>Mineralogical Magazine and Journal of the Mineralogical Society\u003C\u002Fi>,  21 (118) 329-336 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1180\u002Fminmag.1927.021.118.06'>doi:10.1180\u002Fminmag.1927.021.118.06\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002FMinMag\u002FVolume_21\u002F21-118-329.pdf' class='refpdflink'>\u003C\u002Fa>","10.1180\u002Fminmag.1927.021.118.06",{"id":277,"year":278,"html":279,"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":281,"year":282,"html":283,"doi":284},5806969,1960,"Graham, J. (1960) Lattice spacings and colour in the system alumina-chromic oxide. \u003Ci>Journal of Physics and Chemistry of Solids\u003C\u002Fi>, 17. 18-25 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002F0022-3697(60)90170-0'>doi:10.1016\u002F0022-3697(60)90170-0\u003C\u002Fa>","10.1016\u002F0022-3697(60)90170-0",{"id":286,"year":287,"html":288,"doi":289},2028517,1962,"McClure, Donald S. (1962) Optical Spectra of Transition‐Metal Ions in Corundum. \u003Ci>The Journal of Chemical Physics\u003C\u002Fi>,  36 (10) 2757-2779 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1063\u002F1.1732364'>doi:10.1063\u002F1.1732364\u003C\u002Fa>","10.1063\u002F1.1732364",{"id":291,"year":287,"html":292,"doi":293},106799,"Newnham, R. E., de Haan, Y. M. (1962) Refinement of the α Al2O3, Ti2O3, V2O3 and Cr2O3 structures. \u003Ci>Zeitschrift für Kristallographie\u003C\u002Fi>,  117 (2). 235-237 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1524\u002Fzkri.1962.117.2-3.235'>doi:10.1524\u002Fzkri.1962.117.2-3.235\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fzk\u002Fvol117\u002FZK117_235.pdf' class='refpdflink'>\u003C\u002Fa>","10.1524\u002Fzkri.1962.117.2-3.235",{"id":295,"year":287,"html":296,"doi":297},2031960,"McClure, Donald S. (1962) Erratum: Optical Spectra of Transition‐Metal Ions in Corundum. \u003Ci>The Journal of Chemical Physics\u003C\u002Fi>,  37 (7) 1571 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1063\u002F1.1733331'>doi:10.1063\u002F1.1733331\u003C\u002Fa>","10.1063\u002F1.1733331",{"id":299,"year":300,"html":301,"doi":302},107083,1964,"Saalfeld, H. (1964) Strukturuntersuchungen im System Al\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>–Cr\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>. \u003Ci>Zeitschrift für Kristallographie\u003C\u002Fi>,  120 (4-5). 342-348 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1524\u002Fzkri.1964.120.4-5.342'>doi:10.1524\u002Fzkri.1964.120.4-5.342\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fzk\u002Fvol120\u002FZK120_342.pdf' class='refpdflink'>\u003C\u002Fa>","10.1524\u002Fzkri.1964.120.4-5.342",{"id":304,"year":300,"html":305,"doi":306},107085,"Moss, S. C., Newnham, R. E. (1964) The chromium position in ruby. \u003Ci>Zeitschrift für Kristallographie\u003C\u002Fi>,  120 (4). 359-363 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1524\u002Fzkri.1964.120.4-5.359'>doi:10.1524\u002Fzkri.1964.120.4-5.359\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fzk\u002Fvol120\u002FZK120_359.pdf' class='refpdflink'>\u003C\u002Fa>","10.1524\u002Fzkri.1964.120.4-5.359",{"id":308,"year":309,"html":310,"doi":11},16106625,1967,"Porto, S.P.S., Krishnan, R.S. (1967) Raman effect of corundum. The Journal of Chemical Physics: 47(3): 1009-1012.",{"id":312,"year":309,"html":313,"doi":314},107463,"Steinwehr, Η. E. v. (1967) Gitterkonstanten im System α-(Al, Fe, Cr)\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub> und ihr Abweichen von der Vegardregel. \u003Ci>Zeitschrift für Kristallographie\u003C\u002Fi>,  125 (1-6). 377-403 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1524\u002Fzkri.1967.125.16.377'>doi:10.1524\u002Fzkri.1967.125.16.377\u003C\u002Fa>","10.1524\u002Fzkri.1967.125.16.377",{"id":316,"year":317,"html":318,"doi":319},73671,1972,"Anastasiou, P., Seifert, F. (1972) Solid solubility of Al2O3 in enstatite at high temperatures and 1?5 kb water pressure. \u003Ci>Contributions to Mineralogy and Petrology\u003C\u002Fi>,  34 (4) 272-287 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1007\u002Fbf00373758'>doi:10.1007\u002Fbf00373758\u003C\u002Fa>","10.1007\u002Fbf00373758",{"id":321,"year":317,"html":322,"doi":11},16106627,"Yates, B., Cooper, R.F., Pojur, A.F. (1972) Thermal expansion at elevated temperatures: II. Aluminium oxide: experimental data between 100 and 800 K and their analysis. Journal of Physics C: Solid State Physics: 5: 1046-1058.",{"id":324,"year":325,"html":326,"doi":327},74495,1977,"Arima, Makoto, Onuma, Kosuke (1977) solubility of alumina in enstatite and the phase equilibria in the join MgSiO3-MgAl2SiO6 at 10-25 kbar. \u003Ci>Contributions to Mineralogy and Petrology\u003C\u002Fi>,  61 (3). 251-265 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1007\u002Fbf00376700'>doi:10.1007\u002Fbf00376700\u003C\u002Fa>","10.1007\u002Fbf00376700",{"id":329,"year":330,"html":331,"doi":11},16106629,1986,"Franzini M., Troysi M., Cecchini A.(1986): La microdurezza del corindone. Atti Soc. Sc. Nat. Mem. Serie A, 93, 87-100.",{"id":333,"year":334,"html":335,"doi":11},17090994,1997,"Hughes, Richard W. (1997) \u003Ci>Ruby & Sapphire\u003C\u002Fi>. RWH Publishing.",{"id":337,"year":338,"html":339,"doi":11},16106630,1998,"Sutherland, F.L., Hoskin, P.W.O., Fanning, C.M., and Coenraads, R.R. (1998) Models of corundum origin from alkali basaltic terrains: a reappraisal. Contributions to Mineralogy and Petrology: 133: 356-372.",{"id":341,"year":342,"html":343,"doi":11},16106631,2004,"Paglia, G. (2004): Determination of the Structure of γ-Alumina using Empirical and First Principles Calculations combined with Supporting Experiments. D.Ph. Thesis, Faculty of Science, Department of Applied Physics and Department of Applied Chemistry, Curtin University of Technology, 342 pp.",{"id":345,"year":346,"html":347,"doi":11},16963809,2005,"(2005) Corundum. \u003Ci>Handbook of Mineralogy\u003C\u002Fi>. Mineralogical Society of America \u003Ca target='_blank' href='https:\u002F\u002Fwww.handbookofmineralogy.org\u002Fpdfs\u002Fcorundum.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":349,"year":350,"html":351,"doi":11},17217352,2010,"Rondeau, Benjamin, Fritsch, Emmanuel (2010) La morphologie du corindon [The morphology of corundum], in \u003Ci>Saphirs et Rubis de France\u003C\u002Fi>. \u003Ci>Le Règne Minéral\u003C\u002Fi>,  16 (93) 24-27",{"id":353,"year":354,"html":355,"doi":11},16106632,2016,"Sorokina, E.S., Hofmeister, W., Häger, T., Mertz-Kraus, R., Buhre, S., Saul, J.M. (2016) Morphological and chemical evolution of corundum (ruby and sapphire): Crystal ontogeny reconstructed by EMPA, LA-ICP-MS, and Cr3+ Raman mapping. American Mineralogist: 101: 2716-2722.",{"id":357,"year":358,"html":359,"doi":11},16106633,2017,"Wong, J., Verdel, C., Allen, C.M. (2017) Trace-element compositions of sapphire and ruby from the eastern Australian gemstone belt. Mineralogical Magazine: 81: 1551-1576.",{"id":361,"year":358,"html":362,"doi":11},17515481,"Overlin, Stuart (ed.) (2017) Sapphire. \u003Ci>14th Sinkankas Symposium\u003C\u002Fi>,  14. Lotus Gemology.",{"id":364,"year":358,"html":365,"doi":11},17515488,"Emmett, John (2017) All the Colors of Corundum, in \u003Ci>Sapphire\u003C\u002Fi>. \u003Ci>14th Sinkankas Symposium\u003C\u002Fi>,  14. Lotus Gemology. 48-70",{"id":367,"year":368,"html":369,"doi":370},17073660,2020,"Balan, Etienne (2020) Theoretical infrared spectra of OH defects in corundum (α-Al\u003Csub>2\u003C\u002Fsub>O\u003Csub>3\u003C\u002Fsub>) \u003Ci>European Journal of Mineralogy\u003C\u002Fi>,  32 (5) 457-467 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.5194\u002Fejm-32-457-2020'>doi:10.5194\u002Fejm-32-457-2020\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Fejm.copernicus.org\u002Farticles\u002F32\u002F457\u002F2020\u002Fejm-32-457-2020.pdf' class='refpdflink'>\u003C\u002Fa>","10.5194\u002Fejm-32-457-2020",{"id":372,"year":373,"html":374,"doi":375},17712650,2024,"Eßl, Werner, Reiss, Georg, Trasca, Raluca Andreea, Sistaninia, Masoud, Raninger, Peter, Lohrasbi, Sina (2024) The Melt–Crystal Interface in the Production of Monocrystalline Sapphire via Heat Exchanger Method—Numerical Simulation Aspects. \u003Ci>Crystals\u003C\u002Fi>,  14 (12).  \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.3390\u002Fcryst14121036'>doi:10.3390\u002Fcryst14121036\u003C\u002Fa>","10.3390\u002Fcryst14121036",{"id":377,"year":378,"html":379,"doi":380},19750063,2026,"Sorokina, Elena S.; Schmitt, Axel K.; Häger, Tobias; Hopp, Jens (2026) High-spatial-resolution oxygen isotopic analysis to distinguish natural from synthetic corundum. \u003Ci>European Journal of Mineralogy\u003C\u002Fi>,  38 (2). 123-134 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.5194\u002Fejm-38-123-2026'>doi:10.5194\u002Fejm-38-123-2026\u003C\u002Fa>","10.5194\u002Fejm-38-123-2026",[382,390,397,407,417,422,427,436,440,446,455,465,470,478,483,490,497,505,513,520,528,536,542,547,554,562,570,577,586,595,604],{"id":383,"source_url":384,"license_code":385,"credit_html":386,"title":387,"description":7,"author":11,"original_width":388,"original_height":389},6346,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=95006","Public domain","Unknown author, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=95006\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum.jpg",360,323,{"id":391,"source_url":392,"license_code":393,"credit_html":394,"title":7,"description":11,"author":11,"original_width":395,"original_height":396},29533,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F114884","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\u002F114884\" rel=\"noopener\">Department of Geology, TalTech\u003C\u002Fa> via Europeana",1000,666,{"id":398,"source_url":399,"license_code":400,"credit_html":401,"title":402,"description":403,"author":404,"original_width":405,"original_height":406},50802,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=656651","CC BY-SA 2.5","No machine-readable author provided. Zimbres assumed (based on copyright claims)., via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=656651\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Alkaline pegmatite.jpg","\u003Cp>Alkaline pegmatite\nDescription: weathered feldspar and blue corundum crystals. Sample size: 35 x 15 cm.\nOrigin:Canaã alkaline massif, Rio de Janeiro, Brazil\nDate:24\u002F03\u002F2006\nAuthor:Eurico Zimbres\n\u003C\u002Fp>\nFree for all use","No machine-readable author provided. Zimbres assumed (based on copyright claims).",2407,1490,{"id":408,"source_url":409,"license_code":410,"credit_html":411,"title":412,"description":413,"author":414,"original_width":415,"original_height":416},6347,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1340975","CC BY-SA 3.0","Ra'ike (see also Ra'ike on de.wikipedia, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1340975\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Several corundum crystals.jpg","several corundum crystals","Ra'ike (see also Ra'ike on de.wikipedia",1677,1331,{"id":418,"source_url":419,"license_code":393,"credit_html":420,"title":7,"description":11,"author":11,"original_width":395,"original_height":421},29534,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F42832","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F42832\" rel=\"noopener\">Department of Geology, TalTech\u003C\u002Fa> via Europeana",836,{"id":423,"source_url":424,"license_code":393,"credit_html":425,"title":7,"description":11,"author":11,"original_width":395,"original_height":426},29535,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F42828","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F42828\" rel=\"noopener\">Department of Geology, TalTech\u003C\u002Fa> via Europeana",692,{"id":428,"source_url":429,"license_code":393,"credit_html":430,"title":431,"description":432,"author":433,"original_width":434,"original_height":435},6349,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=90371641","Masha Milshina, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=90371641\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Red corundum fluorescence.jpg","Red corundum fluorescence in ultraviolet rays.","Masha Milshina",4004,2000,{"id":437,"source_url":438,"license_code":393,"credit_html":439,"title":7,"description":11,"author":11,"original_width":395,"original_height":396},29536,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F113187","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F113187\" rel=\"noopener\">Department of Geology, TalTech\u003C\u002Fa> via Europeana",{"id":441,"source_url":442,"license_code":443,"credit_html":444,"title":7,"description":11,"author":11,"original_width":395,"original_height":445},29537,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F92233","CC BY-SA 4.0","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F92233\" rel=\"noopener\">The Estonian Museum of Natural History\u003C\u002Fa> via Europeana",919,{"id":447,"source_url":448,"license_code":443,"credit_html":449,"title":450,"description":451,"author":452,"original_width":453,"original_height":454},50803,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113717404","Koreller, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113717404\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Muséum de Nantes - 088 - Corindon brut.jpg","Corindon brut, au Muséum de Nantes","Koreller",4272,2848,{"id":456,"source_url":457,"license_code":458,"credit_html":459,"title":460,"description":461,"author":462,"original_width":463,"original_height":464},6351,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=137830096","CC BY 2.0","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=137830096\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum crystals.jpg","(from left to right: 1.6 centimeters across, 2.3 centimeters across, 1.2 centimeters across, 1.3 centimeters across)\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 5900 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).  The oxide minerals include species that are hydroxy-oxides.  The hydroxide minerals (those with one or more OH-) are usually considered together with the oxides.  Many sulfide minerals are not stable in Earth-surface conditions.  In the presence of oxygen and moisture, sulfide minerals tend to tarnish or alter to oxides and hydroxy-oxides.  All except the most inert elements (such as the platinum-group elements and gold and noble gases) readily form oxides.  Gold oxide forms only under special conditions.\n\u003C\u002Fp>\u003Cp>Corundum is aluminum oxide - Al2O3.  At H≡9, it is the hardest common mineral, apart from diamond.  Corundum forms hexagonal crystals, which is evident even in many river-worn specimens.  The hexagonal columns of corundum typically have well-developed flat tops & bottoms.  These flat ends are not cleavage planes - corundum has no cleavage.  The cleavage-looking flat tops & bottoms of corundum are called partings (pseudocleavage).  Additional breakages will not be along planar surfaces.\n\u003C\u002Fp>\u003Cp>The color of corundum is variable - it can be any color, including plaid patterns.  If transparent and relatively fracture-free & inclusion-free, corundum is said to be of gem-quality, and the color determines the name of the gem.\n\u003C\u002Fp>\u003Cp>deep red = ruby\nblue = sapphire\npale red = sapphire\npale green = sapphire\npurple = sapphire\nyellow = sapphire\n\u003C\u002Fp>\u003Cp>Locality: unrecorded \u002F undisclosed\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of corundum:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=1136","James St. John",2129,813,{"id":466,"source_url":467,"license_code":443,"credit_html":468,"title":7,"description":11,"author":11,"original_width":469,"original_height":395},29538,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F164604","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F164604\" rel=\"noopener\">University of Tartu, Natural History Museum\u003C\u002Fa> via Europeana",726,{"id":471,"source_url":472,"license_code":458,"credit_html":473,"title":474,"description":475,"author":462,"original_width":476,"original_height":477},6352,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=157038183","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=157038183\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum 5.jpg","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 5900 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\u003Cp>The oxide minerals all contain one or more oxide anions (O-2).  The oxide minerals include species that are hydroxy-oxides.  The hydroxide minerals (those with one or more OH-) are usually considered together with the oxides.  Many sulfide minerals are not stable in Earth-surface conditions.  In the presence of oxygen and moisture, sulfide minerals tend to tarnish or alter to oxides and hydroxy-oxides.  All except the most inert elements (such as the platinum-group elements and gold and noble gases) readily form oxides.  Gold oxide forms only under special conditions.\n\u003C\u002Fp>\u003Cp>Corundum is aluminum oxide - Al2O3.  At H≡9, it is the hardest common mineral, apart from diamond.  Corundum forms hexagonal crystals, which is evident even in many river-worn specimens.  The hexagonal columns of corundum typically have well-developed flat tops & bottoms.  These flat ends are not cleavage planes - corundum has no cleavage.  The cleavage-looking flat tops & bottoms of corundum are called partings (pseudocleavage).  Additional breakages will not be along planar surfaces.\n\u003C\u002Fp>\u003Cp>The color of corundum is variable - it can be any color, including plaid patterns.  If transparent and relatively fracture-free and inclusion-free, corundum is said to be of gem-quality, and the color determines the name of the gem.\n\u003C\u002Fp>\u003Cp>deep red = ruby\nblue = sapphire\npale red \u002F pink = sapphire\npale green = sapphire\npurple = sapphire\nyellow = sapphire\n\u003C\u002Fp>\u003Cp>Locality: unrecorded \u002F undisclosed\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of corundum:\n\u003C\u002Fp>\nwww.mindat.org\u002Fgallery.php?min=1136",2200,1301,{"id":479,"source_url":480,"license_code":443,"credit_html":481,"title":7,"description":11,"author":11,"original_width":395,"original_height":482},29539,"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F128439","Photo: Unknown author — http:\u002F\u002Fcreativecommons.org\u002Flicenses\u002Fby-sa\u002F4.0\u002F, courtesy of \u003Ca href=\"https:\u002F\u002Fgeocollections.info\u002Ffile\u002F128439\" rel=\"noopener\">University of Tartu, Natural History Museum\u003C\u002Fa> via Europeana",921,{"id":484,"source_url":485,"license_code":458,"credit_html":486,"title":487,"description":475,"author":462,"original_width":488,"original_height":489},6353,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=157038201","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=157038201\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum 6.jpg",2011,1718,{"id":491,"source_url":492,"license_code":458,"credit_html":493,"title":494,"description":495,"author":462,"original_width":496,"original_height":109},7605,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500074","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500074\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 3 (49143949381).jpg","\u003Cp>Anyolite from the Precambrian of Tanzania. (public display, Dakota Dinosaur Museum, Dickinson, North Dakota, USA\n\u003C\u002Fp>\u003Cp>Green = Cr-zoisite\nBlack = amphibole\nReddish = ruby (corundum)\n\u003C\u002Fp>\u003Cp>This attractive rock is called anyolite, or corundum-amphibole zoisitite (or corundum-amphibole zoisite metamorphite).  Anyolite is a metamorphic rock consisting of finely-crystalline chromian zoisite (green, Ca2Al3(Si2O7)(SiO4)O(OH) - calcium aluminum hydroxy-oxysilicate with Cr impurity) with minor chromian amphibole (black, apparently either chromian tschermakite and\u002For chromian edenite) and some large porphyroblasts of red corundum (ruby) (Al2O3 - aluminum oxide with Cr impurity).  There’s also minor Ca-rich plagioclase feldspar (anorthite, CaAl2Si2O8) in this rock.\n\u003C\u002Fp>\u003Cp>Origin: Published mineralogy studies indicate that this chromian zoisite-ruby combination is the result of very high-grade metamorphism of anorthosite, an intrusive igneous rock dominated by Ca-rich plagioclase feldspar.  The chromium (Cr) in the zoisite and the corundum (ruby = corundum with chromium impurity) is derived from metamorphic alteration of chromite crystals (FeCr2O4 - iron chromium oxide) in the original anorthosite unit.  Chromite and chromitite (= chromite-dominated igneous rock) are commonly associated with anorthosites in LLIs (= large layered igneous intrusions, such as Montana’s Stillwater Complex).\n\u003C\u002Fp>\u003Cp>Geologic Context & Age: This Tanzanian anyolite is hosted in gneisses exposed in the Mozambique Collision Belt, an ancient, north-south trending, tectonic collision zone in eastern Africa.  It dates to the Pan-African Orogeny (Neoproterozoic), during which the ancient continents of West Gondwana (~modern-day South America & Africa) and East Gondwana (~modern-day India-Australia-Antarctica) collided, forming the long-lived, small supercontinent Gondwana.\n\u003C\u002Fp>\u003Cp>Locality: Mundarara Mine, ~27 km west of Longido, northeastern Tanzania, southeastern Africa (2° 37.876’ South latitude, 36° 28.421’ East longitude)\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Mostly synthesized from:\n\u003C\u002Fp>\u003Cp>Game, P.M.  1954.  Zoisite-amphibolite with corundum from Tanganyika.  Mineralogical Magazine 30: 458-466.\n\u003C\u002Fp>\nMercier, A., P. Debat & J.M. Paul.  1999.  Exotic origin of the ruby deposits of the Mangari area in SE Kenya.  Ore Geology Reviews 14: 83-104.",3003,{"id":498,"source_url":499,"license_code":458,"credit_html":500,"title":501,"description":502,"author":462,"original_width":503,"original_height":504},83802,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500075","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500075\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 2 (49144140952).jpg","\u003Cp>Anyolite from the Precambrian of Tanzania. (public display, Idaho Museum of Natural History, Pocatello, Idaho, USA)\n\u003C\u002Fp>\u003Cp>Green = Cr-zoisite\nBlack = amphibole\nReddish = ruby (corundum)\n\u003C\u002Fp>\u003Cp>This attractive rock is called anyolite, or corundum-amphibole zoisitite (or corundum-amphibole zoisite metamorphite).  Anyolite is a metamorphic rock consisting of finely-crystalline chromian zoisite (green, Ca2Al3(Si2O7)(SiO4)O(OH) - calcium aluminum hydroxy-oxysilicate with Cr impurity) with minor chromian amphibole (black, apparently either chromian tschermakite and\u002For chromian edenite) and some large porphyroblasts of red corundum (ruby) (Al2O3 - aluminum oxide with Cr impurity).  There’s also minor Ca-rich plagioclase feldspar (anorthite, CaAl2Si2O8) in this rock.\n\u003C\u002Fp>\u003Cp>Origin: Published mineralogy studies indicate that this chromian zoisite-ruby combination is the result of very high-grade metamorphism of anorthosite, an intrusive igneous rock dominated by Ca-rich plagioclase feldspar.  The chromium (Cr) in the zoisite and the corundum (ruby = corundum with chromium impurity) is derived from metamorphic alteration of chromite crystals (FeCr2O4 - iron chromium oxide) in the original anorthosite unit.  Chromite and chromitite (= chromite-dominated igneous rock) are commonly associated with anorthosites in LLIs (= large layered igneous intrusions, such as Montana’s Stillwater Complex).\n\u003C\u002Fp>\u003Cp>Geologic Context & Age: This Tanzanian anyolite is hosted in gneisses exposed in the Mozambique Collision Belt, an ancient, north-south trending, tectonic collision zone in eastern Africa.  It dates to the Pan-African Orogeny (Neoproterozoic), during which the ancient continents of West Gondwana (~modern-day South America & Africa) and East Gondwana (~modern-day India-Australia-Antarctica) collided, forming the long-lived, small supercontinent Gondwana.\n\u003C\u002Fp>\u003Cp>Locality: Mundarara Mine, ~27 km west of Longido, northeastern Tanzania, southeastern Africa (2° 37.876’ South latitude, 36° 28.421’ East longitude)\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Mostly synthesized from:\n\u003C\u002Fp>\u003Cp>Game, P.M.  1954.  Zoisite-amphibolite with corundum from Tanganyika.  Mineralogical Magazine 30: 458-466.\n\u003C\u002Fp>\nMercier, A., P. Debat & J.M. Paul.  1999.  Exotic origin of the ruby deposits of the Mangari area in SE Kenya.  Ore Geology Reviews 14: 83-104.",2868,1850,{"id":506,"source_url":507,"license_code":458,"credit_html":508,"title":509,"description":510,"author":462,"original_width":511,"original_height":512},83803,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500078","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500078\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 5 (49143985086).jpg","\u003Cp>Anyolite from the Precambrian of Tanzania. (public display, Field Museum of Natural History, Chicago, Illinois, USA)\n\u003C\u002Fp>\u003Cp>Green = Cr-zoisite\nBlack = amphibole\nReddish = ruby (corundum)\n\u003C\u002Fp>\u003Cp>This attractive rock is called anyolite, or corundum-amphibole zoisitite (or corundum-amphibole zoisite metamorphite).  Anyolite is a metamorphic rock consisting of finely-crystalline chromian zoisite (green, Ca2Al3(Si2O7)(SiO4)O(OH) - calcium aluminum hydroxy-oxysilicate with Cr impurity) with minor chromian amphibole (black, apparently either chromian tschermakite and\u002For chromian edenite) and some large porphyroblasts of red corundum (ruby) (Al2O3 - aluminum oxide with Cr impurity).  There’s also minor Ca-rich plagioclase feldspar (anorthite, CaAl2Si2O8) in this rock.\n\u003C\u002Fp>\u003Cp>Origin: Published mineralogy studies indicate that this chromian zoisite-ruby combination is the result of very high-grade metamorphism of anorthosite, an intrusive igneous rock dominated by Ca-rich plagioclase feldspar.  The chromium (Cr) in the zoisite and the corundum (ruby = corundum with chromium impurity) is derived from metamorphic alteration of chromite crystals (FeCr2O4 - iron chromium oxide) in the original anorthosite unit.  Chromite and chromitite (= chromite-dominated igneous rock) are commonly associated with anorthosites in LLIs (= large layered igneous intrusions, such as Montana’s Stillwater Complex).\n\u003C\u002Fp>\u003Cp>Geologic Context & Age: This Tanzanian anyolite is hosted in gneisses exposed in the Mozambique Collision Belt, an ancient, north-south trending, tectonic collision zone in eastern Africa.  It dates to the Pan-African Orogeny (Neoproterozoic), during which the ancient continents of West Gondwana (~modern-day South America & Africa) and East Gondwana (~modern-day India-Australia-Antarctica) collided, forming the long-lived, small supercontinent Gondwana.\n\u003C\u002Fp>\u003Cp>Locality: Mundarara Mine, ~27 km west of Longido, northeastern Tanzania, southeastern Africa (2° 37.876’ South latitude, 36° 28.421’ East longitude)\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Mostly synthesized from:\n\u003C\u002Fp>\u003Cp>Game, P.M.  1954.  Zoisite-amphibolite with corundum from Tanganyika.  Mineralogical Magazine 30: 458-466.\n\u003C\u002Fp>\nMercier, A., P. Debat & J.M. Paul.  1999.  Exotic origin of the ruby deposits of the Mangari area in SE Kenya.  Ore Geology Reviews 14: 83-104.",3011,1863,{"id":514,"source_url":515,"license_code":458,"credit_html":516,"title":517,"description":510,"author":462,"original_width":518,"original_height":519},83804,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500080","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500080\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 6 (49143489888).jpg",2841,1792,{"id":521,"source_url":522,"license_code":385,"credit_html":523,"title":524,"description":525,"author":526,"original_width":527,"original_height":527},2499,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1955956","Dave Dyet http:\u002F\u002Fwww.shutterstone.com http:\u002F\u002Fwww.dyet.com, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1955956\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Baddeleyite in corundum gneiss near Bozeman Gallatin County Montana 2184.jpg","These mineral images are free to use how you wish.","Dave Dyet http:\u002F\u002Fwww.shutterstone.com http:\u002F\u002Fwww.dyet.com",900,{"id":529,"source_url":530,"license_code":458,"credit_html":531,"title":532,"description":533,"author":462,"original_width":534,"original_height":535},7604,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500070","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500070\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 1 (15098298782).jpg","\u003Cp>Anyolite from the Precambrian of Tanzania. (4.7 centimeters across at its widest)\n\u003C\u002Fp>\u003Cp>Green = Cr-zoisite\nBlack = amphibole\nReddish = ruby (corundum)\n\u003C\u002Fp>\u003Cp>This attractive rock is called anyolite, or corundum-amphibole zoisitite (or corundum-amphibole zoisite metamorphite).  Anyolite is a metamorphic rock consisting of finely-crystalline chromian zoisite (green, Ca2Al3(Si2O7)(SiO4)O(OH) - calcium aluminum hydroxy-oxysilicate with Cr impurity) with minor chromian amphibole (black, apparently either chromian tschermakite and\u002For chromian edenite) and some large porphyroblasts of red corundum (ruby) (Al2O3 - aluminum oxide with Cr impurity).  There’s also minor Ca-rich plagioclase feldspar (anorthite, CaAl2Si2O8) in this rock.\n\u003C\u002Fp>\u003Cp>Origin: Published mineralogy studies indicate that this chromian zoisite-ruby combination is the result of very high-grade metamorphism of anorthosite, an intrusive igneous rock dominated by Ca-rich plagioclase feldspar.  The chromium (Cr) in the zoisite and the corundum (ruby = corundum with chromium impurity) is derived from metamorphic alteration of chromite crystals (FeCr2O4 - iron chromium oxide) in the original anorthosite unit.  Chromite and chromitite (= chromite-dominated igneous rock) are commonly associated with anorthosites in LLIs (= large layered igneous intrusions, such as Montana’s Stillwater Complex).\n\u003C\u002Fp>\u003Cp>Geologic Context & Age: This Tanzanian anyolite is hosted in gneisses exposed in the Mozambique Collision Belt, an ancient, north-south trending, tectonic collision zone in eastern Africa.  It dates to the Pan-African Orogeny (Neoproterozoic), during which the ancient continents of West Gondwana (~modern-day South America & Africa) and East Gondwana (~modern-day India-Australia-Antarctica) collided, forming the long-lived, small supercontinent Gondwana.\n\u003C\u002Fp>\u003Cp>Locality: Mundarara Mine, ~27 km west of Longido, northeastern Tanzania, southeastern Africa (2° 37.876’ South latitude, 36° 28.421’ East longitude)\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Mostly synthesized from:\n\u003C\u002Fp>\u003Cp>Game, P.M.  1954.  Zoisite-amphibolite with corundum from Tanganyika.  Mineralogical Magazine 30: 458-466.\n\u003C\u002Fp>\nMercier, A., P. Debat & J.M. Paul.  1999.  Exotic origin of the ruby deposits of the Mangari area in SE Kenya.  Ore Geology Reviews 14: 83-104.",1149,704,{"id":537,"source_url":538,"license_code":385,"credit_html":539,"title":540,"description":525,"author":526,"original_width":541,"original_height":541},7936,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1956031","Dave Dyet http:\u002F\u002Fwww.shutterstone.com http:\u002F\u002Fwww.dyet.com, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1956031\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum emery 3159.jpg",1800,{"id":543,"source_url":544,"license_code":385,"credit_html":545,"title":546,"description":525,"author":526,"original_width":541,"original_height":541},7937,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1956032","Dave Dyet http:\u002F\u002Fwww.shutterstone.com http:\u002F\u002Fwww.dyet.com, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=1956032\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum emery 3160.jpg",{"id":548,"source_url":549,"license_code":458,"credit_html":550,"title":551,"description":552,"author":462,"original_width":553,"original_height":354},7938,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=35018004","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=35018004\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundite (emery rock), Naxos Emery Deposits Greece.jpg","\u003Cp>Corundite (emery rock) (broken surface, dry) with corundum\u002Fsapphire (blue) and calcite (yellowish-brown).\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Corundite is a remarkable metamorphic rock.  The sample shown here has an attractive bluish color and wisps of yellow-brown.  Its composition and origin are quite unusual.  Corundite (a.k.a. emery rock) is dominated by corundum, a very hard (H ≡9) aluminum oxide mineral (Al2O3).  This particular rock has blue corundum, therefore it can be called sapphire.  Rock-forming corundum is rare.\n\u003C\u002Fp>\u003Cp>This material comes from the Naxos Emery Deposits on the island of Naxos in the Aegean Sea.  Naxos is dominated by metamorphic rocks and some igneous rocks.  Much of the island consists of marbles (originally limestones).  Some of the original limestones had lenses of bauxite, which is a rock having aluminum hydroxy-oxide minerals.  Upon metamorphism, the limestones were converted to marbles and the bauxites were converted to diasporites (= diaspore (AlO·OH)-dominated rocks).\n\u003C\u002Fp>\u003Cp>Upon further metamorphism, the diasporites were converted to corundites plus water.  High fluid pressures fractured the rocks, and the fractures got filled up with corundite.\n\u003C\u002Fp>\u003Cp>Metamorphism on Naxos occurred during the Cenozoic in two main phases.  A high-grade metamorphic event occurred during the Eocene, at about 40-50 million years ago.  A second, intermediate-grade metamorphic event occurred during the Early Miocene, at 16-20 million years ago.\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Info. synthesized from:\n\u003C\u002Fp>\u003Cp>Urai & Feenstra (2001) - Weakening associated with the diaspore-corundum dehydration reaction in metabauxites: an example from Naxos (Greece).  Journal of Structural Geology 23: 941-950.\n\u003C\u002Fp>\nFeenstra & Wunder (2002) - Dehydration of diasporite to corundite in nature and experiment.  Geology 30(2): 119-122.",3072,{"id":555,"source_url":556,"license_code":458,"credit_html":557,"title":558,"description":559,"author":462,"original_width":560,"original_height":561},7939,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=35018013","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=35018013\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundite (emery rock) slabbed Naxos Emery Deposits.jpg","\u003Cp>Corundite (emery rock) (cut, wet surface, 10.0 cm across) with blue corundum\u002Fsapphire and yellowish-brown calcite.  The bluish-brownish corundite is a fracture filling.  The host rock can be seen on the left side of the specimen - a chloritoid-hematite-rich diasporite (dark green = chloritoid; red spots = hematite).\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Corundite is a remarkable metamorphic rock.  The sample shown here has an attractive bluish color and wisps of yellow-brown.  Its composition and origin are quite unusual.  Corundite (a.k.a. emery rock) is dominated by corundum, a very hard (H ≡9) aluminum oxide mineral (Al2O3).  This particular rock has blue corundum, therefore it can be called sapphire.  Rock-forming corundum is rare.\n\u003C\u002Fp>\u003Cp>This material comes from the Naxos Emery Deposits on the island of Naxos in the Aegean Sea.  Naxos is dominated by metamorphic rocks and some igneous rocks.  Much of the island consists of marbles (originally limestones).  Some of the original limestones had lenses of bauxite, which is a rock having aluminum hydroxy-oxide minerals.  Upon metamorphism, the limestones were converted to marbles and the bauxites were converted to diasporites (= diaspore (AlO·OH)-dominated rocks) (= very dark green area on the left side of the first photo).\n\u003C\u002Fp>\u003Cp>Upon further metamorphism, the diasporites were converted to corundites plus water.  High fluid pressures fractured the rocks, and the fractures got filled up with corundite.\n\u003C\u002Fp>\u003Cp>Metamorphism on Naxos occurred during the Cenozoic in two main phases.  A high-grade metamorphic event occurred during the Eocene, at about 40-50 million years ago.  A second, intermediate-grade metamorphic event occurred during the Early Miocene, at 16-20 million years ago.\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Info. synthesized from:\n\u003C\u002Fp>\u003Cp>Urai & Feenstra (2001) - Weakening associated with the diaspore-corundum dehydration reaction in metabauxites: an example from Naxos (Greece).  Journal of Structural Geology 23: 941-950.\n\u003C\u002Fp>\nFeenstra & Wunder (2002) - Dehydration of diasporite to corundite in nature and experiment.  Geology 30(2): 119-122.",1693,823,{"id":563,"source_url":564,"license_code":458,"credit_html":565,"title":566,"description":567,"author":462,"original_width":568,"original_height":569},8681,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500082","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500082\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 8 (49144234192).jpg","\u003Cp>Anyolite from the Precambrian of Tanzania. (public dispaly, Carnegie Mus. of Natural History, Pittsburgh, Pennsylvania, USA)\n\u003C\u002Fp>\u003Cp>Green = Cr-zoisite\nBlack = amphibole\nReddish = ruby (corundum)\n\u003C\u002Fp>\u003Cp>This sculpture, entitled \"Sea World\", is carved from an attractive rock is called anyolite, or corundum-amphibole zoisitite (or corundum-amphibole zoisite metamorphite).  Anyolite is a metamorphic rock consisting of finely-crystalline chromian zoisite (green, Ca2Al3(Si2O7)(SiO4)O(OH) - calcium aluminum hydroxy-oxysilicate with Cr impurity) with minor chromian amphibole (black, apparently either chromian tschermakite and\u002For chromian edenite) and some large porphyroblasts of red corundum (ruby) (Al2O3 - aluminum oxide with Cr impurity).  There’s also minor Ca-rich plagioclase feldspar (anorthite, CaAl2Si2O8) in this rock.\n\u003C\u002Fp>\u003Cp>Origin: Published mineralogy studies indicate that this chromian zoisite-ruby combination is the result of very high-grade metamorphism of anorthosite, an intrusive igneous rock dominated by Ca-rich plagioclase feldspar.  The chromium (Cr) in the zoisite and the corundum (ruby = corundum with chromium impurity) is derived from metamorphic alteration of chromite crystals (FeCr2O4 - iron chromium oxide) in the original anorthosite unit.  Chromite and chromitite (= chromite-dominated igneous rock) are commonly associated with anorthosites in LLIs (= large layered igneous intrusions, such as Montana’s Stillwater Complex).\n\u003C\u002Fp>\u003Cp>Geologic Context & Age: This Tanzanian anyolite is hosted in gneisses exposed in the Mozambique Collision Belt, an ancient, north-south trending, tectonic collision zone in eastern Africa.  It dates to the Pan-African Orogeny (Neoproterozoic), during which the ancient continents of West Gondwana (~modern-day South America & Africa) and East Gondwana (~modern-day India-Australia-Antarctica) collided, forming the long-lived, small supercontinent Gondwana.\n\u003C\u002Fp>\u003Cp>Locality: Mundarara Mine, ~27 km west of Longido, northeastern Tanzania, southeastern Africa (2° 37.876’ South latitude, 36° 28.421’ East longitude)\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Mostly synthesized from:\n\u003C\u002Fp>\u003Cp>Game, P.M.  1954.  Zoisite-amphibolite with corundum from Tanganyika.  Mineralogical Magazine 30: 458-466.\n\u003C\u002Fp>\nMercier, A., P. Debat & J.M. Paul.  1999.  Exotic origin of the ruby deposits of the Mangari area in SE Kenya.  Ore Geology Reviews 14: 83-104.",1816,3294,{"id":571,"source_url":572,"license_code":458,"credit_html":573,"title":574,"description":510,"author":462,"original_width":575,"original_height":576},37831,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500073","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84500073\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 4 (49143983001).jpg",2823,1823,{"id":578,"source_url":579,"license_code":410,"credit_html":580,"title":581,"description":582,"author":583,"original_width":584,"original_height":585},55850,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10136424","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10136424\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum-Muscovite-63975.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCorundum\" class=\"extiw\" title=\"en:Corundum\">Corundum\u003C\u002Fa> (Var.: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FRuby\" class=\"extiw\" title=\"en:Ruby\">Ruby\u003C\u002Fa>), \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMuscovite\" class=\"extiw\" title=\"en:Muscovite\">Muscovite\u003C\u002Fa> (Var.: \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FMuscovite\" class=\"extiw\" title=\"en:Muscovite\">Fuchsite\u003C\u002Fa>)\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Eswatini (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-24757.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Lustrous, platy, green fuchsite liberally covers massive ruby matrix on this classic, old-time specimen from South Africa. Fuchsite is the chrome-rich variety of muscovite, which has bright red fluorescence. The piece comes with a Hugh Ford label, a prominent United States dealer from the 1920s to early 1950s. Ex Carl Davis Collection. 6.9 x 4.5 x 2.2 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Robert M. Lavinsky",381,550,{"id":587,"source_url":588,"license_code":443,"credit_html":589,"title":590,"description":591,"author":592,"original_width":593,"original_height":594},58741,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=44914828","Strekeisen, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=44914828\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Elba island.JPG","Corundum crystal (with blue core), biotite (brown) and green hercynite (spinel group) in a MME (Mafic microgranular enclaves) in the S.Andrea granite. Elba Island, Italy. Plane polarized light image, magnification 10x (Field of view = 2mm)","Strekeisen",2592,1728,{"id":596,"source_url":597,"license_code":410,"credit_html":598,"title":599,"description":600,"author":601,"original_width":602,"original_height":603},68165,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7306582","Watstinwoods, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7306582\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","HKU Stephen Hui Museum Rock Mineral 金剛砂 Carborundum SiC.JPG","\u003Cp>\u003Ca href=\"https:\u002F\u002Fzh.wikipedia.org\u002Fwiki\u002F%E9%A6%99%E6%B8%AF%E5%A4%A7%E5%AD%B8%E8%A8%B1%E5%A3%AB%E8%8A%AC%E5%9C%B0%E8%B3%AA%E5%8D%9A%E7%89%A9%E9%A4%A8\" class=\"extiw\" title=\"zh:香港大學許士芬地質博物館\">zh:香港大學許士芬地質博物館\u003C\u002Fa>\n\u003C\u002Fp>\n\u003Ca href=\"https:\u002F\u002Fzh.wikipedia.org\u002Fwiki\u002F%E9%87%91%E5%89%9B%E7%A0%82\" class=\"extiw\" title=\"zh:金剛砂\">金剛砂\u003C\u002Fa>","Watstinwoods",1600,1200,{"id":605,"source_url":606,"license_code":607,"credit_html":608,"title":609,"description":610,"author":611,"original_width":612,"original_height":613},79865,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202344","CC BY-SA 2.0","Pacific Museum of Earth from Canada, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=118202344\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Corundum in Smaragdite (47122077144).jpg","North Carolina, USA","Pacific Museum of Earth from Canada",4000,6000,[615,622,627,631,636],{"id":616,"url":617,"label":618,"formula":619,"spacegroup":620,"year":621},3243,"\u002Fcif\u002F3243.cif","Wang 1994","Al2 O3","R -3 c",1994,{"id":623,"url":624,"label":625,"formula":619,"spacegroup":620,"year":626},3244,"\u002Fcif\u002F3244.cif","Kirfel 1990",1990,{"id":628,"url":629,"label":630,"formula":619,"spacegroup":620,"year":626},3245,"\u002Fcif\u002F3245.cif","Lutterotti 1990",{"id":632,"url":633,"label":634,"formula":619,"spacegroup":620,"year":635},3246,"\u002Fcif\u002F3246.cif","Tsirelson 1985",1985,{"id":637,"url":638,"label":639,"formula":619,"spacegroup":620,"year":640},3247,"\u002Fcif\u002F3247.cif","Lewis 1982",1982,[642,643,644,645,646,647,648,649,650,651,652,653,654,655,656,657,658,659,660,661,662,663,664,665,666,667,668,669,670,671,672,673,674,675,676,677,678],"a-Corundum","Adamas siderites","Ajatit","Alumina","Ayatit","Ayatita","Ayatite","Corindon adamantin","Corindon harmophane","Corinendum","Corinindum","Corivendum","Corivindum","Corrindon","Corundit","Corundita","Corundum-alpha","Corundum-α","Corundumit","Corundumita","Corundumite","Demantspath","Harmophane","Karund","Korunduvit","Korunduvita","Korunduvite","Soimontit","Soimontita","Soimontite","Spath Adamantin","White Sapphire","Zircolita","Zircolite","Zircolith","α-Alumina","α-Corundum",[680,684,688,694,697,701,705,708,712,715,719,723,727,730,735,739,743,749,752,756,762,767,776,779,783,786,790,794,798,801,804,808,812,818,821,825,830,834,838,842,845,848,851,855,858,862,865,869,874,878,882,885,888,891,894,898,901,904,909,914,918,923,926,929,933,936,940,944,947,951,954,957,960,964,969,973,978,981,984,987,991,995,999,1002,1005,1008,1011,1014,1017],{"lang":681,"names":682},"af",[683],"Korund",{"lang":685,"names":686},"an",[687],"Corindón",{"lang":689,"names":690},"ar",[691,692,693],"قرند","كورندم","كوروند",{"lang":695,"names":696},"az",[683],{"lang":698,"names":699},"be",[700],"Карунд",{"lang":702,"names":703},"be-tarask",[704],"карунд",{"lang":706,"names":707},"be-x-old",[700],{"lang":709,"names":710},"bg",[711],"Корунд",{"lang":713,"names":714},"bs",[683],{"lang":716,"names":717},"ca",[718],"corindó",{"lang":720,"names":721},"cs",[722],"korund",{"lang":724,"names":725},"cy",[726],"corwndwm",{"lang":728,"names":729},"da",[683],{"lang":731,"names":732},"de",[733,734,683],"Adamantin","Edelkorund",{"lang":736,"names":737},"el",[738],"Κορούνδιο",{"lang":740,"names":741},"eo",[742],"Korundo",{"lang":744,"names":745},"es",[746,747,748],"corindón","corundo","óxido de aluminio",{"lang":750,"names":751},"et",[683],{"lang":753,"names":754},"eu",[755],"Korindoi",{"lang":757,"names":758},"fa",[759,760,761],"کرندوم","کرندون","کوراندوم",{"lang":763,"names":764},"fi",[765,766],"amarylli","korundi",{"lang":768,"names":769},"fr",[770,771,648,772,649,650,773,662,774,775,675],"1302-74-5","Alumine alpha","corindon","Corundite","Spath adamantin","Télésie",{"lang":777,"names":778},"fy",[683],{"lang":780,"names":781},"ga",[782],"corandam",{"lang":784,"names":785},"gl",[746],{"lang":787,"names":788},"hak",[789],"Kông-ngiu̍k",{"lang":791,"names":792},"he",[793],"קורונדום",{"lang":795,"names":796},"hi",[797],"कुरुविन्द",{"lang":799,"names":800},"hr",[683],{"lang":802,"names":803},"hu",[722],{"lang":805,"names":806},"hy",[807],"Կորունդ",{"lang":809,"names":810},"ia",[811],"Corundo",{"lang":813,"names":814},"id",[7,815,816,817],"Korundum","Kurundam","Α-aluminum oksida",{"lang":819,"names":820},"io",[742],{"lang":822,"names":823},"it",[824],"corindone",{"lang":826,"names":827},"ja",[828,829],"コランダム","鋼玉",{"lang":831,"names":832},"ka",[833],"კორუნდი",{"lang":835,"names":836},"kk",[837,711],"Жоңқытас",{"lang":839,"names":840},"kk-arab",[841],"كورۋند",{"lang":843,"names":844},"kk-cn",[841],{"lang":846,"names":847},"kk-cyrl",[711],{"lang":849,"names":850},"kk-kz",[711],{"lang":852,"names":853},"kk-latn",[854],"Korwnd",{"lang":856,"names":857},"kk-tr",[854],{"lang":859,"names":860},"ko",[861],"강옥",{"lang":863,"names":864},"la",[7],{"lang":866,"names":867},"lt",[868],"Korundas",{"lang":870,"names":871},"lv",[872,873],"Barklijīts","Korunds",{"lang":875,"names":876},"mg",[877],"Kôrindôna",{"lang":879,"names":880},"mk",[881],"корунд",{"lang":883,"names":884},"nb",[722],{"lang":886,"names":887},"nl",[7,722,815],{"lang":889,"names":890},"nn",[722],{"lang":892,"names":893},"no",[683],{"lang":895,"names":896},"oc",[897],"Corindon",{"lang":899,"names":900},"os",[881],{"lang":902,"names":903},"pl",[722],{"lang":905,"names":906},"ps",[907,908],"کورنډم","کوروند",{"lang":910,"names":911},"pt",[912,913],"Corindo","coríndon",{"lang":915,"names":916},"pt-br",[917,913],"corindo",{"lang":919,"names":920},"ro",[772,921,683,922],"corinvindum","zircolit",{"lang":924,"names":925},"ru",[881],{"lang":927,"names":928},"sah",[711],{"lang":930,"names":931},"sat",[932],"ᱠᱳᱨᱩᱱᱰᱟᱢ",{"lang":934,"names":935},"sh",[683],{"lang":937,"names":938},"si",[939],"කුරුවින්ද",{"lang":941,"names":942},"sk",[683,943],"Leukozafír",{"lang":945,"names":946},"sl",[722],{"lang":948,"names":949},"sr",[950,881],"коринвиндум",{"lang":952,"names":953},"sr-ec",[711],{"lang":955,"names":956},"sr-el",[683],{"lang":958,"names":959},"sv",[683],{"lang":961,"names":962},"ta",[963],"குருந்தம்",{"lang":965,"names":966},"th",[967,968],"กะรุน","คอรันดัม",{"lang":970,"names":971},"tr",[972],"Korendon",{"lang":974,"names":975},"ug",[976,977],"ئاليۇمىن ئوكسىدى","ياقۇت",{"lang":979,"names":980},"uk",[711],{"lang":982,"names":983},"uz",[683],{"lang":985,"names":986},"vi",[7],{"lang":988,"names":989},"wuu",[990],"刚玉",{"lang":992,"names":993},"yue",[994],"剛玉",{"lang":996,"names":997},"zh",[990,994,998,829],"金剛砂",{"lang":1000,"names":1001},"zh-cn",[990],{"lang":1003,"names":1004},"zh-hans",[990],{"lang":1006,"names":1007},"zh-hant",[994],{"lang":1009,"names":1010},"zh-hk",[994],{"lang":1012,"names":1013},"zh-sg",[990],{"lang":1015,"names":1016},"zh-tw",[994],{"lang":1018,"names":1019},"zh-yue",[994],"Q131777",{"history":1022,"applications":1026},{"markdown":1023,"model_version":1024,"prompt_version":1025,"reviewed_at":11},"Long before anyone had a single word for it, corundum hid behind a scattering of old gem names. Writers called the red and blue stones adamant, sapphire, ruby, hyacinthos and asteria — all, we now know, the same mineral wearing different colours[1]. In China, four polished corundum axes from the Liangzhu and Sanxingcun cultures, dated to about 2500 BC, show the stone was being worked into tools that early[2].\n\nThe modern name arrived in the early 18th century. In 1725 the English naturalist John Woodward wrote it as *corinvindum*, borrowing from the Sanskrit *kuruvinda* — a word for ruby[3]. The root runs deeper still, into the Tamil-Dravidian *kurundam*, meaning ruby-sapphire[4]. The spelling settled into its present form in 1794, when the Irish chemist Richard Kirwan first used *corundum*[5].\n\n### Making it in the laboratory\n\nThe 19th century turned corundum from a found stone into a made one. In 1837 the French chemist Marc Antoine Gaudin produced the first synthetic rubies, heating alumina — aluminium oxide — with a trace of chromium for colour[6]. A decade later, in 1847, J. J. Ebelmen grew white synthetic sapphires by reacting alumina in boric acid[7].\n\nThe breakthrough came from Auguste Verneuil. The French chemist had worked on melting rubies since the 1880s. He sealed his notes with the Paris Academy of Science, then announced the method in 1902[8]. His flame-fusion process drips powdered alumina through an oxyhydrogen flame, letting the molten droplets build up into a single crystal called a *boule*[9]. By 1903 he could make rubies on a commercial scale[10]. It was the first practical way to grow large flawless gems, and it remains the cheapest[11].","claude-opus-4-8","1.0.0",{"markdown":1027,"model_version":1024,"prompt_version":1025,"reviewed_at":11},"At a hardness of 9 on the ten-point Mohs scale — the scratch test that ranks minerals by which can scratch which — corundum is beaten only by diamond[1]. That hardness is the source of nearly everything people do with it. Its main job is to grind, polish and cut other materials.\n\nThe grinding grade is emery, a black granular corundum naturally mixed with iron oxides such as magnetite and hematite[2]. Emery coats sandpaper and the large tools that machine metals, plastics and wood[3]. Most abrasive corundum today is not dug from the ground at all but manufactured from bauxite, the aluminium ore[4]. Natural corundum for abrasives is still mined in Zimbabwe, Pakistan, Afghanistan, Russia, Sri Lanka and India, with emery-grade stone coming from the Greek island of Naxos[5].\n\nThe flame-fusion process makes corundum to order, and that synthetic stock does more than grinding. It is machined into mechanical parts — tubes, rods and bearings[6]. The same hardness gives scratch-resistant optics and the clear covers on watch faces[7]. Because synthetic sapphire stays transparent from ultraviolet through to infrared light, it serves as instrument windows on satellites and spacecraft[8]. Its toughness has also drawn it into ceramic armour[9].\n\nCorundum is also a laser crystal. A rod of synthetic ruby — corundum coloured red by chromium — is the gain medium in the ruby laser, the part that actually amplifies the light[10]. Ruby lasers have given ground to better materials, but they still serve where short pulses of red light are needed[11]. Its red and blue gem varieties, ruby and sapphire, remain the best-known faces of the species, prized as cut stones[12]."]