[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"minerals:one:3236":3},{"id":4,"longid":5,"guid":6,"name":7,"shortcode_ima":8,"entrytype":9,"entrytype_text":10,"varietyof":11,"synid":11,"polytypeof":11,"groupid":11,"weighting":12,"nolocadd":13,"blacklisted":13,"mindat_formula":8,"mindat_formula_note":11,"ima_formula":8,"elements":14,"sigelements":15,"key_elements":16,"impurities":17,"cim":18,"ima_status":19,"ima_notes":11,"ima_history":11,"approval_year":11,"publication_year":11,"discovery_year":11,"strunz10ed1":22,"strunz10ed2":23,"strunz10ed3":24,"strunz10ed4":25,"dana8ed1":22,"dana8ed2":26,"dana8ed3":22,"dana8ed4":22,"csystem":27,"cclass":28,"spacegroup":29,"spacegroupset":30,"a":31,"b":30,"c":30,"alpha":30,"beta":30,"gamma":30,"aerror":11,"berror":11,"cerror":11,"alphaerror":11,"betaerror":11,"gammaerror":11,"va3":11,"z":32,"csmetamict":13,"commentcrystal":33,"twinning":34,"tranglide":11,"parting":11,"epitaxidescription":11,"morphology":11,"tlform":11,"hmin":32,"hmax":35,"hardtype":11,"vhnmin":36,"vhnmax":37,"vhnerror":11,"vhng":38,"vhns":11,"commenthard":11,"dmeas":39,"dmeas2":40,"dcalc":41,"dmeaserror":11,"dcalcerror":11,"commentdense":11,"lustre":42,"lustretype":42,"commentluster":11,"diapheny":43,"streak":44,"colour":44,"commentcolor":11,"colors":45,"streak_colors":48,"luminescence":49,"uv":11,"cleavage":49,"cleavagetype":11,"fracturetype":50,"tenacity":51,"commentbreak":11,"opticaltype":52,"opticalsign":11,"opticalalpha":30,"opticalalpha2":30,"opticalalphaerror":11,"opticalbeta":30,"opticalbeta2":30,"opticalbetaerror":11,"opticalgamma":30,"opticalgamma2":30,"opticalgammaerror":11,"opticalomega":30,"opticalomega2":30,"opticalomegaerror":11,"opticalepsilon":30,"opticalepsilon2":30,"opticalepsilonerror":11,"opticaln":30,"opticaln2":30,"opticalnerror":11,"optical2vcalc":30,"optical2vcalc2":30,"optical2vcalcerror":11,"optical2vmeasured":30,"optical2vmeasured2":30,"optical2vmeasurederror":11,"rimin":11,"rimax":11,"opticaldispersion":11,"opticalpleochroism":11,"opticalpleochorismdesc":11,"opticalbirefringence":11,"opticalcomments":11,"opticalcolour":53,"opticalinternal":11,"opticaltropic":52,"opticalanisotropism":11,"opticalbireflectance":11,"opticalextinction":11,"opticalr":54,"specdispm":11,"ir":11,"electrical":11,"magnetism":11,"thermalbehaviour":11,"other":55,"industrial":56,"occurrence":11,"otheroccurrence":57,"type_specimen_store":11,"description_short":58,"aboutname":59,"rock_parent":11,"rock_parent2":11,"rock_root":9,"rock_bgs_code":11,"meteoritical_code":11,"updttime":60,"reviewed_at":11,"variety_of":11,"varieties":61,"group_members":76,"associates":77,"confused_with":107,"type_localities":108,"occurrence_total":113,"citations":114,"images":154,"structures":525,"synonyms":552,"language_names":578,"wikidata_qid":625,"texts":626},3236,"1:1:3236:6","1ff83e51-3cd1-4a39-a4dd-ff729f428d0f","Native Platinum","Pt",0,"mineral",null,1687,false,[8],[8],[8],"Fe,Ir,Os,Rh,Pd,Au,Cu","1.82",[20,21],"APPROVED","GRANDFATHERED","1","A","F","10","2","Isometric",32,224,"0","3.9231",4,"Cubic crystals","On {111}",4.5,"279","339",100,"14","19","21.472","Metallic","Opaque","Steel grey to dark grey",[46,47],"gray","black",[46],"None","Hackly","malleable","Isotropic","white","(60.5) 400,\r\n(63.8) 440,\r\n(66.3) 480,\r\n(68.6) 520,\r\n(70.2) 560,\r\n(71.2) 600,\r\n(71.8) 640,\r\n(72.4) 680,\r\n(72.8) 700","Non-magnetic to distinctly magnetic when rich in iron.","Catalysts, jewelry","Mafic and ultramafic rocks.","Palladium-Platinum Series.\r\n\r\nNote that true native platinum in the mineralogical species sense is a rather rare mineral, and most of the specimens so labelled are in fact isoferroplatinum or intimate mixtures of isoferroplatinum and tetraferroplatinum.","From Spanish \"platina\", diminutive of \"plata\", silver. The new metal found in large placer deposits during the sixteenth-century Spanish conquest of South America was called \"platina del Pinto\" after the Rio Pinto, Colombia.","2025-11-10 19:51:47",[62,67,72],{"id":63,"name":64,"entrytype":65,"csystem":11,"ima_formula":11,"mindat_formula":66,"hmin":11,"hmax":11,"dmeas":30,"dcalc":11,"primary_image_id":11},10657,"Palladium-bearing Platinum",2,"(Pt,Pd)",{"id":68,"name":69,"entrytype":65,"csystem":11,"ima_formula":11,"mindat_formula":70,"hmin":32,"hmax":35,"dmeas":71,"dcalc":11,"primary_image_id":11},6057,"Polyxene","(Pt,Fe,Cu,Ni,Pd,Rh)","15",{"id":73,"name":74,"entrytype":65,"csystem":11,"ima_formula":11,"mindat_formula":75,"hmin":11,"hmax":11,"dmeas":30,"dcalc":11,"primary_image_id":11},6716,"Rhodic Platinum","(Pt,Rh)",[],[78,86,94,101],{"id":79,"name":80,"entrytype":9,"csystem":81,"ima_formula":82,"mindat_formula":82,"hmin":83,"hmax":83,"dmeas":30,"dcalc":84,"primary_image_id":85},745,"Bowieite","Orthorhombic","Rh\u003Csub>2\u003C\u002Fsub>S\u003Csub>3\u003C\u002Fsub>",7,"6.93",3757,{"id":87,"name":88,"entrytype":9,"csystem":27,"ima_formula":89,"mindat_formula":90,"hmin":91,"hmax":91,"dmeas":30,"dcalc":92,"primary_image_id":93},1186,"Cuproiridsite","Cu(Ir\u003Csup>3+\u003C\u002Fsup>Ir\u003Csup>4+\u003C\u002Fsup>)S\u003Csub>4\u003C\u002Fsub>","(Cu,Fe)Ir\u003Csub>2\u003C\u002Fsub>S\u003Csub>4\u003C\u002Fsub>",5.5,"7.24",6647,{"id":95,"name":96,"entrytype":9,"csystem":27,"ima_formula":97,"mindat_formula":97,"hmin":35,"hmax":91,"dmeas":98,"dcalc":99,"primary_image_id":100},1401,"Erlichmanite","OsS\u003Csub>2\u003C\u002Fsub>","8.28","9.59",8004,{"id":102,"name":103,"entrytype":9,"csystem":81,"ima_formula":104,"mindat_formula":104,"hmin":105,"hmax":105,"dmeas":30,"dcalc":106,"primary_image_id":100},2164,"Kashinite","Ir\u003Csub>2\u003C\u002Fsub>S\u003Csub>3\u003C\u002Fsub>",7.5,"9.10",[],[109],{"id":110,"txt":111,"latitude":11,"longitude":11,"country":112},741,"Pinto River, Novita, Chocó Department, Colombia","Colombia",472,[115,119,123,127,131,136,140,144,149],{"id":116,"year":117,"html":118,"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":120,"year":121,"html":122,"doi":11},16120332,1958,"Schneiderhöhn (1958) 315.",{"id":124,"year":125,"html":126,"doi":11},15051970,1975,"Cabri, Louis J., Feather, Clive E. (1975) Platinum-Iron Alloys: A Nomenclature Based on a Study of Natural and Synthetic Alloys. \u003Ci>The Canadian Mineralogist\u003C\u002Fi>,  13 (2) 117-126",{"id":128,"year":129,"html":130,"doi":11},17111046,1991,"Harris, D. C., Cabri, L. J. (1991) Nomenclature of platinum-group-element alloys: review and revision. \u003Ci>The Canadian Mineralogist\u003C\u002Fi>,  29 (2) 231-237 \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Frruff_1.0\u002Fuploads\u002FCM29_231.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":132,"year":133,"html":134,"doi":135},63622,2002,"Fleet, M. E.; De Almeida, C. M.; Angeli, N. (2002) Botryoidal platinum, palladium and potarite from the Bom Sucesso stream, Minas Gerais, Brazil: compositional zoning and origin. \u003Ci>The Canadian Mineralogist\u003C\u002Fi>,  40 (2). 341-355 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2113\u002Fgscanmin.40.2.341'>doi:10.2113\u002Fgscanmin.40.2.341\u003C\u002Fa> \u003Ca target='_blank' href='https:\u002F\u002Frruff.info\u002Fdoclib\u002Fcm\u002Fvol40\u002FCM40_341.pdf' class='refpdflink'>\u003C\u002Fa>","10.2113\u002Fgscanmin.40.2.341",{"id":137,"year":138,"html":139,"doi":11},16966742,2005,"(2005) Platinum. \u003Ci>Handbook of Mineralogy\u003C\u002Fi>. Mineralogical Society of America \u003Ca target='_blank' href='https:\u002F\u002Fwww.handbookofmineralogy.org\u002Fpdfs\u002Fplatinum.pdf' class='refpdflink'>\u003C\u002Fa>",{"id":141,"year":142,"html":143,"doi":11},16120336,2013,"Bindi, L., Zaccarini, F., Garuti, G., and Angeli, N. (2013) The solid solution between platinum and palladium in nature. Mineralogical Magazine 77, 269-274.",{"id":145,"year":146,"html":147,"doi":148},1003386,2016,"Reith, Frank, Zammit, Carla M., Shar, Sahar S., Etschmann, Barbara, Bottrill, Ralph, Southam, Gordon, Ta, Christine, Kilburn, Matthew, Oberthür, Thomas, Ball, Andrew S., Brugger, Joël (2016) Biological role in the transformation of platinum-group mineral grains. \u003Ci>Nature Geoscience\u003C\u002Fi>,  9 (4) 294-298 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1038\u002Fngeo2679'>doi:10.1038\u002Fngeo2679\u003C\u002Fa>","10.1038\u002Fngeo2679",{"id":150,"year":151,"html":152,"doi":153},16511578,2023,"Junge, Malte, Goldmann, Simon, Wotruba, Hermann (2023) Mineralogy and mineral chemistry of detrital platinum-group minerals and gold particles from the Elbe, Germany. \u003Ci>European Journal of Mineralogy\u003C\u002Fi>,  35 (4) 439-459 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.5194\u002Fejm-35-439-2023'>doi:10.5194\u002Fejm-35-439-2023\u003C\u002Fa>","10.5194\u002Fejm-35-439-2023",[155,165,174,184,192,201,209,219,229,238,246,253,261,267,277,286,294,301,309,317,325,332,339,346,353,360,368,375,382,390,399,407,414,421,429,437,444,452,460,468,476,483,490,497,504,511,518],{"id":156,"source_url":157,"license_code":158,"credit_html":159,"title":160,"description":161,"author":162,"original_width":163,"original_height":164},17269,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=478129","Public domain","Aram Dulyan (User:Aramgutang), via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=478129\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum nuggets.jpg","An assortment of nuggets of native platinum from \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCalifornia\" class=\"extiw\" title=\"w:California\">California\u003C\u002Fa> (top-left) and \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSierra_Leone\" class=\"extiw\" title=\"w:Sierra Leone\">Sierra Leone\u003C\u002Fa> (top-right and bottom). The bottom nuggets show impressions of the enclosing matrix. Photograph taken at the \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNatural_History_Museum\" class=\"extiw\" title=\"w:Natural History Museum\">Natural History Museum\u003C\u002Fa>, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FLondon\" class=\"extiw\" title=\"w:London\">London\u003C\u002Fa>.","Aram Dulyan (User:Aramgutang)",816,439,{"id":166,"source_url":167,"license_code":168,"credit_html":169,"title":170,"description":171,"author":172,"original_width":173,"original_height":173},17270,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7642671","CC BY 3.0","Jurii, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7642671\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum-crystals.jpg","Two platinum crystals, about 1 cm in size.","Jurii",752,{"id":175,"source_url":176,"license_code":177,"credit_html":178,"title":179,"description":180,"author":181,"original_width":182,"original_height":183},17271,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10171509","CC BY-SA 3.0","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10171509\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum-274992.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FPlatinum\" class=\"extiw\" title=\"en:Platinum\">Platinum\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Fox Gulch, Salmon River - Red Mountain District, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGoodnews_Bay,_Alaska\" class=\"extiw\" title=\"en:Goodnews Bay, Alaska\">Goodnews Bay\u003C\u002Fa>, Bethel Borough, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAlaska\" class=\"extiw\" title=\"en:Alaska\">Alaska\u003C\u002Fa>, USA (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-3286.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: 1.4 x 0.8 x 0.8 cm.\u003C\u002Fdd>\n\u003Cdd>A very rare and excellent native platinum nugget from an uncommon Alaskan locality - Fox Gulch, Goodnews Bay. The lustrous, very lightly rounded, 3-dimensional, sculptural nugget is composed of a multitude of tiny, hoppered, crudely cubic platinum crystals. This piece looks like a tiny, 3-sided, platinum Christmas tree with ornaments and a bent trunk. Rarely availableon the market. Weighs 15.76 carats or just over 3 grams.\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Robert M. Lavinsky",360,546,{"id":185,"source_url":186,"license_code":177,"credit_html":187,"title":188,"description":189,"author":181,"original_width":190,"original_height":191},17272,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10420276","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10420276\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum-4jg29a.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FPlatinum\" class=\"extiw\" title=\"en:Platinum\">Platinum\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Talnakh Cu-Ni Deposit, Noril'sk, Putoran Plateau, \u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FTaymyr_Peninsula\" class=\"extiw\" title=\"en:Taymyr Peninsula\">Taimyr Peninsula\u003C\u002Fa>, Taymyrskiy Autonomous Okrug, Eastern-Siberian Region, Russia (\u003Ca rel=\"nofollow\" class=\"external text\" href=\"http:\u002F\u002Fwww.mindat.org\u002Floc-2751.html\">Locality at mindat.org\u003C\u002Fa>)\u003C\u002Fdd>\n\u003Cdd>Size: thumbnail, .8 x .7 x .5 cm\n\u003Cdl>\u003Cdt>Platinum\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>This is a good reference specimen of CRYSTALLIZED cubic Platinum, very rare for the species. When cubes are found, they are usually malformed. Not these! This is a sharp, well-formed cube of Platinum (to 5 mm on edge) that even has several penetration twins emerging from it. .8 x .7 x .5 cm\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",799,641,{"id":193,"source_url":194,"license_code":168,"credit_html":195,"title":196,"description":197,"author":198,"original_width":199,"original_height":200},69684,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=9774375","Periodictableru, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=9774375\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum crystals.jpg","Crystals of pure platinum grown by gas phase transport.","Periodictableru",2084,1460,{"id":202,"source_url":203,"license_code":177,"credit_html":204,"title":205,"description":206,"author":181,"original_width":207,"original_height":208},17273,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10465063","Robert M. Lavinsky, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=10465063\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum-t07-103b.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FPlatinum\" class=\"extiw\" title=\"en:Platinum\">Platinum\u003C\u002Fa>\n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Locality: Australia\u003C\u002Fdd>\n\u003Cdd>Size: thumbnail, 1.5 x 1.1 x 0.5 cm\n\u003Cdl>\u003Cdt>Platinum\u003C\u002Fdt>\u003C\u002Fdl>\u003C\u002Fdd>\n\u003Cdd>This is a lustrous, waterworn, metallic gray, platinum nugget. It is obviously from an alluvial deposit, and is a very attractive nugget with good heft for the size (7 grams). Platinum is over $1000 per ounce so this is worth $250 or so just in melting weight. ex. Cranbrook Museum with label\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>",400,289,{"id":210,"source_url":211,"license_code":212,"credit_html":213,"title":214,"description":215,"author":216,"original_width":217,"original_height":218},17275,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34570334","CC BY 2.0","U.S. Geological Survey, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34570334\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","The Importance of Platinum Elements.jpg","The U.S. is 90% reliant on imports of PGEs (platinum-group elements) which are essential for cleaning automobile exhaust, for manufacturing glass, fertilizer, high-octane fuel, and a variety of chemicals, including cancer fighting drugs. They are widely used in jewelry and electronics such as hard drives, circuitry, and cell phones. PGEs could also play a crucial role in fuel cell technology to produce clean energy for cars, homes, and businesses.\n\u003Cp>The first-ever inventory and geological assessment of known and undiscovered platinum-group element (PGE) resources estimates that more than 150,000 metric tons of PGEs may exist in the two southern African countries that produce most of the global supply of these critical elements. This is more than 20 times the total tonnage produced since the 1920s when PGE mining began in these countries.\n\u003C\u002Fp>\u003Cp>The identified resources will meet global demand for many decades, given current growth rates and with supplies also coming from recycling, according to the study. About 90% of PGEs in the Earth occur in limited areas of only three countries: South Africa’s Bushveld Complex, Zimbabwe’s Great Dyke, and Russia’s Norilsk region.\n\u003C\u002Fp>\u003Cp>Learn more at on.doi.gov\u002FPGEs\n\u003C\u002Fp>\nPhoto Credit: Chip Clark, Smithsonian Institution","U.S. Geological Survey",1459,964,{"id":220,"source_url":221,"license_code":222,"credit_html":223,"title":224,"description":225,"author":226,"original_width":227,"original_height":228},69690,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113716263","CC BY-SA 4.0","Koreller, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=113716263\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Muséum de Nantes - 040 - Minerai de platine (Bushveldt, Afrique du Sud).jpg","Minerai de platine, en provenance de Bushveldt (Afrique du Sud), au Muséum de Nantes","Koreller",2320,3512,{"id":230,"source_url":231,"license_code":212,"credit_html":232,"title":233,"description":234,"author":235,"original_width":236,"original_height":237},5581,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=97240502","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=97240502\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic chromitite (Merensky Reef, Bushveld Complex, mid-Paleoproterozoic, 2.054-2.055 Ga; Rustenburg Platinum Mine, northeastern South Africa) 1.jpg","Sulfidic chromitite (4.5 cm across at its widest) from the Precambrian of South Africa.\n\u003Cp>LLIs are large layered igneous intrusions.  Famous examples include Montana’s Stillwater Complex, southern Africa’s Great Dike of Rhodesia, the Muskox in Canada, the Dufek in Antarctica, Greenland's Skaergaard Complex, and South Africa's Bushveld Complex.  LLIs consist of thick successions of ultramafic intrusive igneous rocks displaying small-scale to large-scale layering.  The layering in LLIs is the result of crystal settling during cooling of the original magma.  Repeated injections of magma is thought to be necessary in order to get layering throughout the extremely thick sections of rock.  LLIs typically have economic concentrations of important metals (e.g., chromium, platinum).\n\u003C\u002Fp>\u003Cp>This chromium-rich rock is from a platinum mine in the 2.06 billion year old Bushveld Complex, an LLI in South Africa, which has ~75-80% of all the world’s chromium (Cr) reserves.  The Cr is mined from chromitite (chromite-dominated intrusive igneous rocks) - all the black crystals in the rock are chromite (FeCr2O4).  This chromitite also has scattered sulfides (= small, metallic-lustered, brassy gold-colored masses) that are non-platiniferous.  Scattered dark-colored orthopyroxene and grayish-colored plagioclase feldspar are also present.\n\u003C\u002Fp>\u003Cp>Stratigraphy & age: Merensky Reef, uppermost Critical Zone, Rustenburg Layered Suite, Bushveld Complex, mid-Paleoproterozoic, 2.054-2.055 Ga\n\u003C\u002Fp>\nLocality: Level 17, Rustenburg Platinum Mine, northeastern North West Province, northwest of the city of Johannesburg, northeastern South Africa","James St. John",4496,2632,{"id":239,"source_url":240,"license_code":212,"credit_html":241,"title":242,"description":243,"author":235,"original_width":244,"original_height":245},36812,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=155677697","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=155677697\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum (Element - 78) 2.jpg","Platinum (Pt) is # 78 on the Periodic Table of Elements.  Elemental platinum is a silvery-gray metal.  It is the namesake of the \"platinum group elements\" (PGEs, or PGMs - platinum group metals).  Platinum occurs in few minerals, and so is rare and valuable.  It does occur in its native state as a mineral, but is always alloyed with other metals, often other PGEs.  Some placer deposits have platinum-rich nuggets.\n\u003Cp>Platinum also occurs as a significant impurity in some sulfide minerals.  In Montana's Stillwater Complex, platinum and palladium occur within intercumulate chalcopyrite and pyrrhotite in rocks of the Johns-Manville Reef.  Occasionally, a Pt-dominant mineral occurs there, such as braggite ((Pt,Pd,Ni)S, platinum palladium nickel sulfide).\n\u003C\u002Fp>\u003Cp>Forty-four isotopes of platinum are known - six occur naturally.  Platinum-195 and platinum-194 are the most common varieties.  Platinum-190, platinum-192, platinum-196, and platinum-198 occur in lesser to very small amounts.\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Info. at:\nen.wikipedia.org\u002Fwiki\u002FPlatinum\nand\nen.wikipedia.org\u002Fwiki\u002FIsotopes_of_platinum\nand\nwww.flickr.com\u002Fphotos\u002Fjsjgeology\u002Falbums\u002F72157651883953350\u002F\nand\nwww.flickr.com\u002Fphotos\u002Fjsjgeology\u002Falbums\u002F72157646178995492\nand\n\u003C\u002Fp>\nwww.flickr.com\u002Fphotos\u002Fjsjgeology\u002Falbums\u002F72157657784669250",3244,2800,{"id":247,"source_url":248,"license_code":212,"credit_html":249,"title":250,"description":251,"author":235,"original_width":252,"original_height":146},3773,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84501008","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84501008\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Braggite ((Pt,Pd,Ni)S) in sulfidic serpentinite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) (14808934796).jpg","\u003Cp>Braggite in sulfidic serpentinite from the Precambrian of Montana, USA. (field of view 1.7 cm across)\n\u003C\u002Fp>\u003Cp>Silvery area near center = braggite\nBrownish bronze = Pt\u002FPd-rich pyrrhotite\nYellow brassy = Pt\u002FPd-rich chalcopyrite\nDull greenish gray = serpentinite host rock (formerly a dunite)\n\u003C\u002Fp>\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>The J-M Reef has other Pt\u002FPd-rich minerals besides pyrrhotite and chalcopyrite, but they are uncommon to rare.  Shown above is a specimen of the very rare sulfide mineral braggite (= silver-colored patch near the center).  Braggite is platinum-palladium-nickel sulfide - (Pt,Pd,Ni)S.  Macroscopic crystals have been reported from only two localities on Earth - Montana's Stillwater Complex and South Africa's platinum mines.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 50W141 D7 West in the Stillwater Mine (= western side of the D7 level, ~98’ below the 5000’ elevation level, 141’ west of shaft), underground & west of the Stillwater River, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",3072,{"id":254,"source_url":255,"license_code":212,"credit_html":256,"title":257,"description":258,"author":235,"original_width":259,"original_height":260},3775,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896483","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896483\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 4.jpg","Sulfidic serpentinite with braggite from the Precambrian of Montana, USA.\n\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic and mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum-palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt-Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) (= dull brassy colored) and chalcopyrite (CuFeS2) (= yellow brassy colored).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>The J-M Reef has other Pt\u002FPd-rich minerals besides pyrrhotite and chalcopyrite, but they are uncommon to rare.  Seen here is a Stillwater serpentinite with pyrrhotite, chalcopyrite, and a visible mass of braggite (= silver-colored patch near the center of the photo).  Braggite is a very rare sulfide mineral, (Pt,Pd,Ni)S - platinum-palladium-nickel sulfide.  Macroscopic braggite has been reported from two localities on Earth - Montana's Stillwater Complex and South Africa's platinum mines.\n\u003C\u002Fp>\u003Cp>Stratigraphy: \"footwall rocks\" beneath the main olivine-bearing zone associated with the Johns-Manville Reef, Troctolite-Anorthosite I zone, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 50W141 D7 West in the Stillwater Mine (= western side of the D7 level, ~98’ below the 5000’ elevation level, 141’ west of shaft), underground and west of the Stillwater River, southwest of the town of Nye, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",3028,1895,{"id":262,"source_url":263,"license_code":212,"credit_html":264,"title":265,"description":266,"author":235,"original_width":252,"original_height":146},3778,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=124923742","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=124923742\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Braggite ((Pt,Pd,Ni)S) in sulfidic serpentinite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA).jpg","Braggite in sulfidic serpentinite from the Precambrian of Montana, USA. (field of view: 1.7 centimeters across)\n\u003Cp>Silvery area near center = braggite\nBrownish bronze = Pt\u002FPd-rich pyrrhotite\nYellow brassy = Pt\u002FPd-rich chalcopyrite\nDull greenish gray = serpentinite host rock (formerly a dunite)\n\u003C\u002Fp>\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>The J-M Reef has other Pt\u002FPd-rich minerals besides pyrrhotite and chalcopyrite, but they are uncommon to rare.  Shown above is a specimen of the very rare sulfide mineral braggite (= silver-colored patch near the center).  Braggite is platinum-palladium-nickel sulfide - (Pt,Pd,Ni)S.  Macroscopic crystals have been reported from only two localities on Earth - Montana's Stillwater Complex and South Africa's platinum mines.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 50W141 D7 West in the Stillwater Mine (= western side of the D7 level, ~98’ below the 5000’ elevation level, 141’ west of shaft), underground & west of the Stillwater River, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",{"id":268,"source_url":269,"license_code":270,"credit_html":271,"title":272,"description":273,"author":274,"original_width":275,"original_height":276},4271,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=107423731","CC BY 4.0","Makvandi, Sheida and Pagé, Philippe and Tremblay, Jonathan and Girard, Réjean, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=107423731\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","BSE images of platinum-group minerals - Stillwaterite.png","A selection of backscatter electron (BSE) images of platinum-group minerals identified in the till samples. (a) Braggite ((Pt,Pd,Ni)S); (b) Cooperite (PtS); (c) Moncheite ((Pt,Pd)(Te,Bi)2); (d) Stillwaterite (Pd8As3); (e) Mertieite-II (Pd8(Sb,As)3); (f) Taimyrite ((Pd,Cu,Pt)3Sn); (g) Cabriite (Pd2SnCu); (h) Isomertieite (Pd11Sb2As2); (i) Paolovite (Pd2Sn); (j) Potarite (PdHg); (k) Stibiopalladinite (Pd5Sb2); (l) Platinum (Pt). The image is published in an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.","Makvandi, Sheida and Pagé, Philippe and Tremblay, Jonathan and Girard, Réjean",1026,944,{"id":278,"source_url":279,"license_code":212,"credit_html":280,"title":281,"description":282,"author":283,"original_width":284,"original_height":285},5579,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=41697937","jsj1771, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=41697937\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Interlayered hydrogrossular garnetite and chromitite (Transvaal jade) (Critical Zone, Bushveld Complex, Paleoproterozoic, ~2.05 Ga; Bonjanala Platinum District, South Africa) 3.jpg","Interlayered hydrogrossular garnetite and chromitite (\"Transvaal jade\") from the Precambrian of South Africa. (7.4 cm across at its widest)\n\u003Cp>This attractive rock is nicknamed \"Transvaal jade\", but it is not jade.  \"True\" jade refers to either nephrite or jadeitite metamorphic rocks.  Transvaal jade is a greenish garnetite, a crystalline-textured metamorphic rock composed of hydrogrossular garnet.  The black bands are layers of chromitite, which is a granular, crystalline-textured, intrusive igneous rock composed of the mineral chromite (FeCr2O4 - iron chromium oxide).\n\u003C\u002Fp>\u003Cp>This rock has been metamorphosed.  The precursor, or protolith - the original rock before metamorphic alteration - was anorthosite having bands of chromitite.  Anorthosite is a scarce, coarsely-crystalline, intrusive igneous rock composed exclusively, or almost exclusively, of plagioclase feldspar (NaAlSi3O8 to CaAl2Si2O8 - sodium aluminosilicate to calcium aluminosilicate).  The plagioclase feldspar has been metamorphosed to grossular garnet, while the chromitite bands have retained their original mineralogy.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Critical Zone, Western Lobe of the Rustenburg Layered Suite, Bushveld Complex, Paleoproterozoic, ~2.05 Ga\n\u003C\u002Fp>\nLocality: old diggings on the grounds of a Lonmin platinum mine, apparently at or near Buffelsfontein, Bonjanala Platinum District Municipality, North West Province, South Africa","jsj1771",2631,2656,{"id":287,"source_url":288,"license_code":212,"credit_html":289,"title":290,"description":291,"author":235,"original_width":292,"original_height":293},11554,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253387","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253387\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Massive Pt-Pd-rich sulfide (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 2.jpg","Massive sulfide from the Precambrian of Montana, USA.\n\u003Cp>Southern Montana’s Beartooth Mountains has one of the few platinum mines in all of North America.  Platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic and mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum-palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  The Pt-Pd occurs in intercumulate sulfides, typically pale brassy-colored pyrrhotite (Fe1-xS) and yellow-brassy colored chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>Stillwater's intercumulate sulfides usually fill spaces between crystals of plagioclase or pyroxene or olivine\u002Fserpentine.  Occasionally, the sulfide minerals occur in a massive state, such as the J-M Reef sample seen here.  The rock principally contains the usual Pt-Pd-rich chalcopyrite and pyrrhotite.  Other minerals are also present, such as bornite (Cu5FeS4) and small patches of some silvery-colored mineral (what?).  Several rare sulfide and element and element-alloy minerals have been reported from the Stillwater, including hollingworthite ((Rh,Pt,Pd)AsS), native gold (Au), tetraferroplatinum (PtFe), palladobismutharsenide (Pd2(Bi,As)), braggite ((Pt,Pd,Ni)S), keithconnite (Pd3-xTe), moncheite (Pt(Te,Bi)2), vysotskite ((Pd,Ni)S), etc.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 46W500 stope (4600’ elevation above sea level and 500’ west of shaft), Stillwater Mine, underground and west of the Stillwater River, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",2623,2025,{"id":295,"source_url":296,"license_code":212,"credit_html":297,"title":298,"description":291,"author":235,"original_width":299,"original_height":300},11555,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253390","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253390\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Massive Pt-Pd-rich sulfide (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 1.jpg",2664,1957,{"id":302,"source_url":303,"license_code":212,"credit_html":304,"title":305,"description":306,"author":283,"original_width":307,"original_height":308},11835,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=41697938","jsj1771, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=41697938\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Interlayered hydrogrossular garnetite and chromitite (Transvaal jade) (Critical Zone, Bushveld Complex, Paleoproterozoic, ~2.05 Ga; Bonjanala Platinum District, South Africa) 1.jpg","Interlayered hydrogrossular garnetite and chromitite (\"Transvaal jade\") from the Precambrian of South Africa. (8.5 cm across at its widest)\n\u003Cp>This attractive rock is nicknamed \"Transvaal jade\", but it is not jade.  \"True\" jade refers to either nephrite or jadeitite metamorphic rocks.  Transvaal jade is a greenish garnetite, a crystalline-textured metamorphic rock composed of hydrogrossular garnet.  The black bands are layers of chromitite, which is a granular, crystalline-textured, intrusive igneous rock composed of the mineral chromite (FeCr2O4 - iron chromium oxide).\n\u003C\u002Fp>\u003Cp>This rock has been metamorphosed.  The precursor, or protolith - the original rock before metamorphic alteration - was anorthosite having bands of chromitite.  Anorthosite is a scarce, coarsely-crystalline, intrusive igneous rock composed exclusively, or almost exclusively, of plagioclase feldspar (NaAlSi3O8 to CaAl2Si2O8 - sodium aluminosilicate to calcium aluminosilicate).  The plagioclase feldspar has been metamorphosed to grossular garnet, while the chromitite bands have retained their original mineralogy.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Critical Zone, Western Lobe of the Rustenburg Layered Suite, Bushveld Complex, Paleoproterozoic, ~2.05 Ga\n\u003C\u002Fp>\nLocality: old diggings on the grounds of a Lonmin platinum mine, apparently at or near Buffelsfontein, Bonjanala Platinum District Municipality, North West Province, South Africa",3483,2274,{"id":310,"source_url":311,"license_code":212,"credit_html":312,"title":313,"description":314,"author":283,"original_width":315,"original_height":316},11836,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=41697939","jsj1771, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=41697939\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Interlayered hydrogrossular garnetite and chromitite (Transvaal jade) (Critical Zone, Bushveld Complex, Paleoproterozoic, ~2.05 Ga; Bonjanala Platinum District, South Africa) 2.jpg","Interlayered hydrogrossular garnetite and chromitite (\"Transvaal jade\") from the Precambrian of South Africa. (8.6 cm across at its widest)\n\u003Cp>This attractive rock is nicknamed \"Transvaal jade\", but it is not jade.  \"True\" jade refers to either nephrite or jadeitite metamorphic rocks.  Transvaal jade is a greenish garnetite, a crystalline-textured metamorphic rock composed of hydrogrossular garnet.  The black bands are layers of chromitite, which is a granular, crystalline-textured, intrusive igneous rock composed of the mineral chromite (FeCr2O4 - iron chromium oxide).\n\u003C\u002Fp>\u003Cp>This rock has been metamorphosed.  The precursor, or protolith - the original rock before metamorphic alteration - was anorthosite having bands of chromitite.  Anorthosite is a scarce, coarsely-crystalline, intrusive igneous rock composed exclusively, or almost exclusively, of plagioclase feldspar (NaAlSi3O8 to CaAl2Si2O8 - sodium aluminosilicate to calcium aluminosilicate).  The plagioclase feldspar has been metamorphosed to grossular garnet, while the chromitite bands have retained their original mineralogy.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Critical Zone, Western Lobe of the Rustenburg Layered Suite, Bushveld Complex, Paleoproterozoic, ~2.05 Ga\n\u003C\u002Fp>\nLocality: old diggings on the grounds of a Lonmin platinum mine, apparently at or near Buffelsfontein, Bonjanala Platinum District Municipality, North West Province, South Africa",3356,2000,{"id":318,"source_url":319,"license_code":212,"credit_html":320,"title":321,"description":322,"author":235,"original_width":323,"original_height":324},12344,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022724","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022724\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum nuggets (placer platinum) (Granite Creek, southern British Columbia, Canada) (17125947987).jpg","\u003Cp>Platinum nuggets from Canada. (each is ~1 to 2 mm in size)\n\u003C\u002Fp>\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substrance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Platinum (Pt) is far more valuable that gold, but it doesn't have a distinctive, prestigious color.  Like most metals, platinum has a silvery color.  Platinum, when purified, is heavier than gold, but specimen platinum has about the same specific gravity as gold nuggets (about 19).\n\u003C\u002Fp>\u003Cp>Platinum is alway found significantly alloyed with other elements, usually other PGEs (platinum-group elements: platinum (Pt), palladium (Pd), osmium (Os), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru)).  Platinum is typically found in Precambrian ultramafic igneous rocks, but there are also some Pt-bearing placer deposits in Canada, Colombia, and Russia.\n\u003C\u002Fp>\u003Cp>The small platinum nuggets shown above are from a placer deposit in Granite Creek, a tributary of the Tulameen River near Granite City, a ghost town in southern British Columbia, Canada.  This was a significant platinum occurrence.  It's been reported that >20,000 ounces worth of platinum nuggets were recovered from this area from the mid-1880s to the mid-1930s.  Granite Creek platinum nuggets are derived from weathering of PGE-bearing chromitic dunites in the Tulameen Ultramafic Complex of Early Jurassic age.\n\u003C\u002Fp>\u003Cp>Available assay information indicates that Granite Creek nuggets are 68 to 78% platinum (Pt), 4 to 14% osmiridium (Ir,Os), 8 to 10% iron (Fe), 3 to 4% copper (Cu), 3% rhodium (Rh), 1% iridium (Ir), and 0.2% palladium (Pd).\n\u003C\u002Fp>\nLocality: Granite Creek, a tributary of the Tulameen River near Granite City, southern British Columbia, southwestern Canada",1114,998,{"id":326,"source_url":327,"license_code":212,"credit_html":328,"title":329,"description":330,"author":235,"original_width":237,"original_height":331},13088,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84625707","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84625707\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Massive sulfide (bornite & Pt Pd-rich chalcopyrite-pyrrhotite) (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) (14828837001).jpg","\u003Cp>Massive sulfide from the Precambrian of Montana, USA. (4.6 cm across at its widest)\n\u003C\u002Fp>\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>Platinum- and palladium-bearing pyrrhotite & chalcopyrite in the Stillwater Complex usually occur as intercumulate fills between crystals of plagioclase or pyroxene or olivine\u002Fserpentine.  Occasionally, these sulfide minerals occur in a massive state.  This is a fragment of massive sulfide from the Stillwater Complex’s J-M Reef.  The yellowish-gold colored material is Pt\u002FPd-rich chalcopyrite, and the brownish-gold colored material is Pt\u002FPd-rich pyrrhotite.  There are other minerals present, including bornite (Cu5FeS4) (dark, multicolored areas), and small patches of some silvery-colored mineral (what?).  Several rare sulfide and element and element-alloy minerals have been reported from the Stillwater, including hollingworthite ((Rh,Pt,Pd)AsS), gold (Au), tetraferroplatinum (PtFe), palladobismutharsenide (Pd2(Bi,As)), braggite ((Pt,Pd,Ni)S), keithconnite (Pd3-xTe), moncheite (Pt(Te,Bi)2), vysotskite ((Pd,Ni)S), etc.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 46W500 stope (4600’ elevation above sea level & 500’ west of shaft), Stillwater Mine, underground & west of the Stillwater River, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",1807,{"id":333,"source_url":334,"license_code":212,"credit_html":335,"title":336,"description":291,"author":235,"original_width":337,"original_height":338},13089,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253376","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253376\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Massive Pt-Pd-rich sulfide (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 6.jpg",1998,1727,{"id":340,"source_url":341,"license_code":212,"credit_html":342,"title":343,"description":291,"author":235,"original_width":344,"original_height":345},13090,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253380","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253380\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Massive Pt-Pd-rich sulfide (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 5.jpg",2292,1853,{"id":347,"source_url":348,"license_code":212,"credit_html":349,"title":350,"description":291,"author":235,"original_width":351,"original_height":352},13091,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253382","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253382\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Massive Pt-Pd-rich sulfide (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 4.jpg",2121,2181,{"id":354,"source_url":355,"license_code":212,"credit_html":356,"title":357,"description":291,"author":235,"original_width":358,"original_height":359},13092,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253384","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=99253384\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Massive Pt-Pd-rich sulfide (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 3.jpg",2380,2196,{"id":361,"source_url":362,"license_code":212,"credit_html":363,"title":364,"description":365,"author":235,"original_width":366,"original_height":367},17247,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022728","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022728\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum (Russia) 2 (16715067064).jpg","\u003Cp>Platinum mass & well-formed crystals from Russia. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)\n\u003C\u002Fp>\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substrance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Platinum (Pt) is far more valuable that gold, but it doesn't have a distinctive, prestigious color.  Like most metals, platinum has a silvery color.  Platinum, when purified, is heavier than gold, but specimen platinum has about the same specific gravity as gold nuggets (about 19).\n\u003C\u002Fp>\nPlatinum is alway found significantly alloyed with other elements, usually other PGEs (platinum-group elements: platinum (Pt), palladium (Pd), osmium (Os), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru)).  Platinum is typically found in Precambrian ultramafic igneous rocks, but there are also some Pt-bearing placer deposits in Canada, Colombia, and Russia.",1980,1051,{"id":369,"source_url":370,"license_code":212,"credit_html":371,"title":372,"description":365,"author":235,"original_width":373,"original_height":374},17276,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022727","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022727\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum (Russia) 1 (17151301829).jpg",868,576,{"id":376,"source_url":377,"license_code":212,"credit_html":378,"title":379,"description":365,"author":235,"original_width":380,"original_height":381},17278,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022730","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022730\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Platinum (Russia) 4 (17337141151).jpg",2567,1400,{"id":383,"source_url":384,"license_code":212,"credit_html":385,"title":386,"description":387,"author":235,"original_width":388,"original_height":389},17279,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022732","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022732\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Large platinum nugget (replica) (Ural Mountains, Russia) 1 (17337624135).jpg","\u003Cp>Large platinum nugget (replica) from Russia.  (public display, South Dakota School of Mines and Technology Museum of Geology, Rapid City, South Dakota, USA)\n\u003C\u002Fp>\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substrance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>Elements are fundamental substances of matter - matter that is composed of the same types of atoms.  At present, 118 elements are known (four of them are still unnamed).  Of these, 98 occur naturally on Earth (hydrogen to californium).  Most of these occur in rocks & minerals, although some occur in very small, trace amounts.  Only some elements occur in their native elemental state as minerals.\n\u003C\u002Fp>\u003Cp>To find a native element in nature, it must be relatively non-reactive and there must be some concentration process.  Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state as minerals.\n\u003C\u002Fp>\u003Cp>Platinum (Pt) is far more valuable that gold, but it doesn't have a distinctive, prestigious color.  Like most metals, platinum has a silvery color.  Platinum, when purified, is heavier than gold, but specimen platinum has about the same specific gravity as gold nuggets (about 19).\n\u003C\u002Fp>\u003Cp>Platinum is alway found significantly alloyed with other elements, usually other PGEs (platinum-group elements: platinum (Pt), palladium (Pd), osmium (Os), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru)).  Platinum is typically found in Precambrian ultramafic igneous rocks, but there are also some Pt-bearing placer deposits in Canada, Colombia, and Russia.\n\u003C\u002Fp>\nThe replica shown above is that of a large platinum mass found in 1887 in the Ural Mountains of Russia.  Its original weight was about 21 pounds.",3294,1996,{"id":391,"source_url":392,"license_code":222,"credit_html":393,"title":394,"description":395,"author":396,"original_width":397,"original_height":398},17699,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=127445214","David Hospital, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=127445214\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Niggliite & Platinum.jpg","Metallic inclusions of the extremely rare platinum stannide niggliite in a platinum nugget from Alaska (Fox Gulch, Goodnews Bay, Bethel Borough, Alaska, United States of America). Ex Vandenbroucke Museum collection from Waregem, Belgium.","David Hospital",770,577,{"id":400,"source_url":401,"license_code":212,"credit_html":402,"title":403,"description":404,"author":235,"original_width":405,"original_height":406},20378,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34530426","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=34530426\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic bronzitite (platinum-palladium ore) Stillwater Mine MT.jpg","\u003Cp>Sulfidic bronzitite (field of view ~3.65 cm across) from the Johns-Manville Reef, Lower Banded Series, Stillwater Complex (Neoarchean, 2.71 b.y.) in the Stillwater Mine, Beartooth Mountains, Montana, USA.\n\u003C\u002Fp>\u003Cp>Brownish bronze = Pt\u002FPd-rich pyrrhotite.\n\u003C\u002Fp>\u003Cp>Yellow brassy = Pt\u002FPd-rich chalcopyrite.\n\u003C\u002Fp>\u003Cp>Brown = bronzite pyroxene.\n\u003C\u002Fp>\u003Cp>\u003Cbr> \n\u003C\u002Fp>\u003Cp>This is a very high grade platinum ore from the Stillwater Mine's J-M Reef. The platinum\u002Fpalladium-bearing sulfides are here hosted in bronzitite rock, the rarest known host rock in the mine. Bronzitite is a coarsely-crystalline, intrusive igneous rock composed almost entirely of bronzite pyroxene. An alternate name for bronzitite is bronzite pyroxenite (a type of peridotite). What makes this rock so high grade? It is about 25% intercumulate Pt\u002FPd-rich sulfides.\n\u003C\u002Fp>\u003Cp>\u003Cbr> \n\u003C\u002Fp>\u003Cp>This rock has an ore grade of about 10 ounces of Pd-Pt per ton of rock (wow!), with a Pd-Pt ratio of ~3.5:1 (= highest grade platinum group metals deposit in the world). This is the rarest host rock & highest-grade type of platinum ore known at the Stillwater Mine.\n\u003C\u002Fp>\u003Cp>\u003Cbr> \n\u003C\u002Fp>\u003Cp>Locality: small bronzitite lens in the 5300 West 13300 D6 West area of the Stillwater Mine (= western side of the D6 level, ~84' below the 5300' elevation datum & 13,300' west of shaft), Beartooth Mountains, southern Montana, USA.\n\u003C\u002Fp>\n\u003Chr>\n\u003Cpre>-------------------\n\u003C\u002Fpre>\n\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\nThe main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).",945,827,{"id":408,"source_url":409,"license_code":212,"credit_html":410,"title":411,"description":387,"author":235,"original_width":412,"original_height":413},25982,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022731","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=40022731\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Large platinum nugget (replica) (Ural Mountains, Russia) 2 (16715145674).jpg",3697,2217,{"id":415,"source_url":416,"license_code":212,"credit_html":417,"title":418,"description":258,"author":235,"original_width":419,"original_height":420},36804,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896475","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896475\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 11.jpg",4000,1918,{"id":422,"source_url":423,"license_code":212,"credit_html":424,"title":425,"description":426,"author":235,"original_width":427,"original_height":428},36805,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896479","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896479\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 8.jpg","Sulfidic serpentinite with braggite from the Precambrian of Montana, USA.\n\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic and mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum-palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt-Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) (= dull brassy colored) and chalcopyrite (CuFeS2) (= yellow brassy colored).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>The J-M Reef has other Pt\u002FPd-rich minerals besides pyrrhotite and chalcopyrite, but they are uncommon to rare.  Seen here is a Stillwater serpentinite with pyrrhotite, chalcopyrite, and a visible mass of braggite (= silver-colored patch in the lower left portion of the photo).  Braggite is a very rare sulfide mineral, (Pt,Pd,Ni)S - platinum-palladium-nickel sulfide.  Macroscopic braggite has been reported from two localities on Earth - Montana's Stillwater Complex and South Africa's platinum mines.\n\u003C\u002Fp>\u003Cp>Stratigraphy: \"footwall rocks\" beneath the main olivine-bearing zone associated with the Johns-Manville Reef, Troctolite-Anorthosite I zone, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 50W141 D7 West in the Stillwater Mine (= western side of the D7 level, ~98’ below the 5000’ elevation level, 141’ west of shaft), underground and west of the Stillwater River, southwest of the town of Nye, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",3105,2416,{"id":430,"source_url":431,"license_code":212,"credit_html":432,"title":433,"description":434,"author":235,"original_width":435,"original_height":436},36806,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896480","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896480\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 7.jpg","Sulfidic serpentinite with braggite from the Precambrian of Montana, USA.\n\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic and mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum-palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt-Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) (= dull brassy colored) and chalcopyrite (CuFeS2) (= yellow brassy colored).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>The J-M Reef has other Pt\u002FPd-rich minerals besides pyrrhotite and chalcopyrite, but they are uncommon to rare.  Seen here is a Stillwater serpentinite with pyrrhotite, chalcopyrite, and a visible mass of braggite (= silver-colored patch in the upper left portion of the photo).  Braggite is a very rare sulfide mineral, (Pt,Pd,Ni)S - platinum-palladium-nickel sulfide.  Macroscopic braggite has been reported from two localities on Earth - Montana's Stillwater Complex and South Africa's platinum mines.\n\u003C\u002Fp>\u003Cp>Stratigraphy: \"footwall rocks\" beneath the main olivine-bearing zone associated with the Johns-Manville Reef, Troctolite-Anorthosite I zone, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 50W141 D7 West in the Stillwater Mine (= western side of the D7 level, ~98’ below the 5000’ elevation level, 141’ west of shaft), underground and west of the Stillwater River, southwest of the town of Nye, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",3948,2201,{"id":438,"source_url":439,"license_code":212,"credit_html":440,"title":441,"description":434,"author":235,"original_width":442,"original_height":443},36807,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896481","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896481\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 6.jpg",3719,2625,{"id":445,"source_url":446,"license_code":212,"credit_html":447,"title":448,"description":449,"author":235,"original_width":450,"original_height":451},36808,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896482","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896482\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 5.jpg","Sulfidic serpentinite with braggite from the Precambrian of Montana, USA.\n\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic and mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum-palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt-Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) (= dull brassy colored) and chalcopyrite (CuFeS2) (= yellow brassy colored).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>The J-M Reef has other Pt\u002FPd-rich minerals besides pyrrhotite and chalcopyrite, but they are uncommon to rare.  Seen here is a Stillwater serpentinite with pyrrhotite, chalcopyrite, and a visible mass of braggite (= silver-colored patch a bit left of center of the photo).  Braggite is a very rare sulfide mineral, (Pt,Pd,Ni)S - platinum-palladium-nickel sulfide.  Macroscopic braggite has been reported from two localities on Earth - Montana's Stillwater Complex and South Africa's platinum mines.\n\u003C\u002Fp>\u003Cp>Stratigraphy: \"footwall rocks\" beneath the main olivine-bearing zone associated with the Johns-Manville Reef, Troctolite-Anorthosite I zone, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 50W141 D7 West in the Stillwater Mine (= western side of the D7 level, ~98’ below the 5000’ elevation level, 141’ west of shaft), underground and west of the Stillwater River, southwest of the town of Nye, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",2852,1679,{"id":453,"source_url":454,"license_code":212,"credit_html":455,"title":456,"description":457,"author":235,"original_width":458,"original_height":459},37188,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626929","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626929\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic bronzitite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 3 (30800357083).jpg","\u003Cp>Sulfidic bronzitite from the Precambrian of Montana, USA. (field of view ~8.4 cm across)\n\u003C\u002Fp>\u003Cp>Silvery & brassy = Pt\u002FPd-rich pyrrhotite & Pt\u002FPd-rich chalcopyrite\nBrown = bronzite pyroxene\n\u003C\u002Fp>\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>This is a very high grade platinum ore from the Stillwater Mine's J-M Reef.  The platinum\u002Fpalladium-bearing sulfides are here hosted in bronzitite rock, the rarest known host rock in the mine.  Bronzitite is a coarsely-crystalline, intrusive igneous rock composed almost entirely of bronzite pyroxene.  An alternate name for bronzitite is bronzite pyroxenite.  What makes this rock so high grade?  It is about 25% intercumulate Pt\u002FPd-rich sulfides.\n\u003C\u002Fp>\u003Cp>This rock has an ore grade of about 10 ounces of Pd-Pt per ton of rock (wow!), with a Pd-Pt ratio of ~3.5:1 (= highest grade platinum group metals deposit in the world).  This is the rarest host rock & highest-grade type of platinum ore known at the Stillwater Mine.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: small bronzitite lens in the 5300 West 13300 D6 West area of the Stillwater Mine (= western side of the D6 level, ~84' below the 5300' elevation datum & 13,300' west of shaft), Beartooth Mountains, southern Montana, USA",3940,2600,{"id":461,"source_url":462,"license_code":212,"credit_html":463,"title":464,"description":465,"author":235,"original_width":466,"original_height":467},37189,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626930","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626930\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic bronzitite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 2 (31610193425).jpg","\u003Cp>Sulfidic bronzitite from the Precambrian of Montana, USA. (field of view ~10.3 cm across)\n\u003C\u002Fp>\u003Cp>Silvery & brassy = Pt\u002FPd-rich pyrrhotite & Pt\u002FPd-rich chalcopyrite\nBrown = bronzite pyroxene\n\u003C\u002Fp>\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>This is a very high grade platinum ore from the Stillwater Mine's J-M Reef.  The platinum\u002Fpalladium-bearing sulfides are here hosted in bronzitite rock, the rarest known host rock in the mine.  Bronzitite is a coarsely-crystalline, intrusive igneous rock composed almost entirely of bronzite pyroxene.  An alternate name for bronzitite is bronzite pyroxenite.  What makes this rock so high grade?  It is about 25% intercumulate Pt\u002FPd-rich sulfides.\n\u003C\u002Fp>\u003Cp>This rock has an ore grade of about 10 ounces of Pd-Pt per ton of rock (wow!), with a Pd-Pt ratio of ~3.5:1 (= highest grade platinum group metals deposit in the world).  This is the rarest host rock & highest-grade type of platinum ore known at the Stillwater Mine.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: small bronzitite lens in the 5300 West 13300 D6 West area of the Stillwater Mine (= western side of the D6 level, ~84' below the 5300' elevation datum & 13,300' west of shaft), Beartooth Mountains, southern Montana, USA",3860,2220,{"id":469,"source_url":470,"license_code":212,"credit_html":471,"title":472,"description":473,"author":235,"original_width":474,"original_height":475},37190,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626937","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626937\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic bronzitite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 5 (30800356293).jpg","\u003Cp>Sulfidic bronzitite from the Precambrian of Montana, USA. (field of view ~10.6 cm across)\n\u003C\u002Fp>\u003Cp>Silvery & brassy = Pt\u002FPd-rich pyrrhotite & Pt\u002FPd-rich chalcopyrite\nBrown = bronzite pyroxene\n\u003C\u002Fp>\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>This is a very high grade platinum ore from the Stillwater Mine's J-M Reef.  The platinum\u002Fpalladium-bearing sulfides are here hosted in bronzitite rock, the rarest known host rock in the mine.  Bronzitite is a coarsely-crystalline, intrusive igneous rock composed almost entirely of bronzite pyroxene.  An alternate name for bronzitite is bronzite pyroxenite.  What makes this rock so high grade?  It is about 25% intercumulate Pt\u002FPd-rich sulfides.\n\u003C\u002Fp>\u003Cp>This rock has an ore grade of about 10 ounces of Pd-Pt per ton of rock (wow!), with a Pd-Pt ratio of ~3.5:1 (= highest grade platinum group metals deposit in the world).  This is the rarest host rock & highest-grade type of platinum ore known at the Stillwater Mine.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: small bronzitite lens in the 5300 West 13300 D6 West area of the Stillwater Mine (= western side of the D6 level, ~84' below the 5300' elevation datum & 13,300' west of shaft), Beartooth Mountains, southern Montana, USA",3924,2116,{"id":477,"source_url":478,"license_code":212,"credit_html":479,"title":480,"description":481,"author":235,"original_width":419,"original_height":482},37191,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626938","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626938\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic bronzitite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 4 (30800356643).jpg","\u003Cp>Sulfidic bronzitite from the Precambrian of Montana, USA. (field of view ~9.5 cm across)\n\u003C\u002Fp>\u003Cp>Silvery & brassy = Pt\u002FPd-rich pyrrhotite & Pt\u002FPd-rich chalcopyrite\nBrown = bronzite pyroxene\n\u003C\u002Fp>\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic & mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum & palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt & Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) and chalcopyrite (CuFeS2).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>This is a very high grade platinum ore from the Stillwater Mine's J-M Reef.  The platinum\u002Fpalladium-bearing sulfides are here hosted in bronzitite rock, the rarest known host rock in the mine.  Bronzitite is a coarsely-crystalline, intrusive igneous rock composed almost entirely of bronzite pyroxene.  An alternate name for bronzitite is bronzite pyroxenite.  What makes this rock so high grade?  It is about 25% intercumulate Pt\u002FPd-rich sulfides.\n\u003C\u002Fp>\u003Cp>This rock has an ore grade of about 10 ounces of Pd-Pt per ton of rock (wow!), with a Pd-Pt ratio of ~3.5:1 (= highest grade platinum group metals deposit in the world).  This is the rarest host rock & highest-grade type of platinum ore known at the Stillwater Mine.\n\u003C\u002Fp>\u003Cp>Stratigraphy: Johns-Manville Reef, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: small bronzitite lens in the 5300 West 13300 D6 West area of the Stillwater Mine (= western side of the D6 level, ~84' below the 5300' elevation datum & 13,300' west of shaft), Beartooth Mountains, southern Montana, USA",2308,{"id":484,"source_url":485,"license_code":212,"credit_html":486,"title":487,"description":457,"author":235,"original_width":488,"original_height":489},37192,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626941","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=84626941\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Sulfidic bronzitite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 6 (30800355943).jpg",3992,2436,{"id":491,"source_url":492,"license_code":212,"credit_html":493,"title":494,"description":495,"author":235,"original_width":496,"original_height":380},37194,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896469","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896469\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Bronzite in sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 4.jpg","Bronzite in sulfidic serpentinite from the Precambrian of Montana, USA.\n\u003Cp>Southern Montana’s Beartooth Mountains has one of only three platinum mines in North America.  There, platinum and palladium are mined from the 2.71 billion-year-old Stillwater Complex, a classic example of an LLI (large, layered igneous province).  LLIs are large intrusive bodies that display large-scale and small-scale layering, even including cross bedding, ripples, graded bedding, channelforms, and other sedimentary-like features.  The Stillwater started out as a large subsurface mass of slowly cooling magma.  As various minerals crystallized, they settled to the bottom of the magma chamber.  This resulted in layering.  Igneous rocks that formed this way have a cumulate texture.  Currents in the still-liquid portions of the magma chamber produced the sedimentary structures mentioned above.  Most of the Stillwater displays only large-scale layering.\n\u003C\u002Fp>\u003Cp>The rocks in the Stillwater are ultramafic and mafic intrusive igneous rocks.  Common lithologies include gabbros, norites, harzburgites, anorthosites, troctolites, chromitites, pyroxenites, and dunites.  Portions of the Stillwater have been metamorphosed.  Olivine is the most commonly altered component, usually metamorphosed to serpentine.\n\u003C\u002Fp>\u003Cp>The main platinum-palladium occurrence is in the Johns-Manville Reef (J-M Reef), an interval in the lower part of the Lower Banded Series.  There, the Pt-Pd occur in intercumulate sulfides, typically pyrrhotite (Fe1-xS) (= dull brassy colored) and chalcopyrite (CuFeS2) (= yellow brassy colored).  Platinum ores in the J-M Reef are principally sulfidic anorthosites, but other lithologies also occur.  The J-M Reef is the highest grade deposit known for platinum-group elements (PGEs).\n\u003C\u002Fp>\u003Cp>This Stillwater rock is principally a sulfidic serpentinite.  The highly lustrous areas are cleavage planes of bronzite, a type of orthopyroxene.\n\u003C\u002Fp>\u003Cp>Stratigraphy: \"footwall rocks\" beneath the main olivine-bearing zone associated with the Johns-Manville Reef, Troctolite-Anorthosite I zone, Lower Banded Series, Stillwater Complex, Neoarchean, 2.71 Ga\n\u003C\u002Fp>\nLocality: 50W141 D7 West in the Stillwater Mine (= western side of the D7 level, ~98’ below the 5000’ elevation level, 141’ west of shaft), underground and west of the Stillwater River, southwest of the town of Nye, southwestern Stillwater County, Beartooth Mountains, southern Montana, USA",3707,{"id":498,"source_url":499,"license_code":212,"credit_html":500,"title":501,"description":495,"author":235,"original_width":502,"original_height":503},37195,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896471","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896471\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Bronzite in sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 3.jpg",3172,2262,{"id":505,"source_url":506,"license_code":212,"credit_html":507,"title":508,"description":495,"author":235,"original_width":509,"original_height":510},37196,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896472","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896472\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Bronzite in sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 2.jpg",3269,2663,{"id":512,"source_url":513,"license_code":212,"credit_html":514,"title":515,"description":495,"author":235,"original_width":516,"original_height":517},37197,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896473","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896473\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Bronzite in sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 5.jpg",3843,2535,{"id":519,"source_url":520,"license_code":212,"credit_html":521,"title":522,"description":495,"author":235,"original_width":523,"original_height":524},37198,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896474","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=98896474\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Bronzite in sulfidic serpentintite (platinum-palladium ore) (Johns-Manville Reef, Stillwater Complex, Neoarchean, 2.71 Ga; Stillwater Mine, Beartooth Mountains, Montana, USA) 1.jpg",2882,1784,[526,532,537,542,547],{"id":527,"url":528,"label":529,"formula":8,"spacegroup":530,"year":531},11340,"\u002Fcif\u002F11340.cif","Wyckoff 1963","F m 3 m",1963,{"id":533,"url":534,"label":535,"formula":8,"spacegroup":530,"year":536},11341,"\u002Fcif\u002F11341.cif","Owen 1933",1933,{"id":538,"url":539,"label":540,"formula":8,"spacegroup":530,"year":541},11342,"\u002Fcif\u002F11342.cif","Bredig 1927",1927,{"id":543,"url":544,"label":545,"formula":8,"spacegroup":530,"year":546},11343,"\u002Fcif\u002F11343.cif","Barth 1926",1926,{"id":548,"url":549,"label":550,"formula":8,"spacegroup":530,"year":551},11344,"\u002Fcif\u002F11344.cif","Davey 1925",1925,[553,554,555,556,557,558,559,560,561,562,563,564,565,566,567,568,569,570,571,572,573,574,575,576,577],"Bạch kim","Gediegen Platin","Jinmrplati","Plaatina","Plateno","Platí","Platin","Platîn","Platina","Platína","Platină","Platine","Platini","Platino","Platīns","Platinu","Plàtinu","Platinum","Platinwm","Platyna","Polyplatinum","Qullqiya","Λευκόχρυσος","பிளாட்டினம்","പ്ലാറ്റിനം",[579,583,587,591,595,599,603,608,612,616,621],{"lang":580,"names":581},"az",[582],"Sərbəst platin",{"lang":584,"names":585},"ca",[586],"platí natiu",{"lang":588,"names":589},"de",[590],"Platin, gediegen",{"lang":592,"names":593},"fr",[594],"platine natif",{"lang":596,"names":597},"hu",[598],"Termésplatina",{"lang":600,"names":601},"it",[602],"platino nativo",{"lang":604,"names":605},"ja",[606,607],"自然白金","自然白金グループ",{"lang":609,"names":610},"oc",[611],"Platin natiu",{"lang":613,"names":614},"pl",[615],"Platyna rodzima",{"lang":617,"names":618},"ru",[619,620],"платина самородная","самородная платина",{"lang":622,"names":623},"uk",[624],"платина самородна","Q1318438",{"history":11,"applications":11}]