Antimonide, arsenopalladinite group
Specific gravity: 9.5
Hardness: 4 to 5
Colour: Silver, white to steel-grey
Common impurities: Cu,Sn,As
Plutonic igneous environments
Stibiopalladinite is an uncommon constituent of platinum deposits.
Associated minerals include braggite,
cooperite, mertieite II,
alloys, genkinite, platarsite,
geversite, gold and
At the Voisey's Bay Ni-Co-Cu deposit, Voisey´s Bay, Labrador, Newfoundland and Labrador, Canada, the platinum group sulphides occur in a hornblende gabbro dyke. The dominant platinum group minerals are sperrylite, paolovite, tin-bearing stibiopalladinite, michenerite, froodite and maslovite (CM 49.1505-1522).
At the Wellgreen Cu-Ni-PGE deposit, Kluane District, Whitehorse mining district, Yukon, Canada, a large variety of platinum-group minerals, associated with base-metal sulphides, include sperrylite, stibiopalladinite or mertieite II (or both), geversite, copper–nickel rich tetraferroplatinum, native platinum, isoferroplatinum, froodite (?), hollingworthite, laurite, native iridium, rhodium-bearing cobaltite–gersdorffite and palladium-bearing ullmannite (CM 40. 651-669).
At the Kevitsa Ni-Cu-platinum group element mine, Kevitsansarvi, Sodankylä, Lapland, Finland, identified platinum group minerals include moncheite, merenskyite, michenerite, platinum and palladium rich melonite, and minerals of the kotulskite–sobolevskite–sudburyite solid-solution series. Sperrylite grains are also abundant. Other platinum group minerals encountered are cooperite, braggite, platinum-iron alloys and mertieite II or stibiopalladinite. Some grains of native gold also were found (CM 40.377-394).
At the Pustaya River, Kamchatka Krai, Russia, platinum-group minerals were recovered from the placer deposit. The concentrate consists of platinum nuggets, except for two grains, an iridium nugget and palladium-bearing gold. The platinum nuggets are represented by native platinum, isoferroplatinum and a platinum–iron alloy with an elevated concentration of palladium. Minerals found as inclusions in the platinum nuggets include osmium, cooperite, vysotskite, platarsite, hollingworthite, irarsite, sperrylite, keithconnite, stibiopalladinite, rhodarsenide, vasilite and rhodium-bearing pyrrhotite (CM 38.1251-1264).
At the Noril'sk ore field, Putoran Plateau, Taimyr Peninsula, Taymyrskiy Autonomous Okrug, Krasnoyarsk Krai, Russia, widespread minerals from the medium stage of crystallisation include antimony-bearing paolovite, insizwaite–geversite, antimony-bearing niggliite, tetraferroplatinum, palladium-rustenburgite–atokite–zvyagintsevite, moncheite, majakite, plumbopalladinite, polarite and stibiopalladinite, commonly in association with altaite. Stannopalladinite, palladium-rich tatyanaite–taimyrite, cupriferous gold–palladium–platinum–tetra-auricupride and cuproauride, often enriched in silver, have been identified among late-crystallised minerals of the medium stage (CM 54.429-452).
At Nizhnii Tagil, Sverdlovsk Oblast, Russia, platinum group minerals observed in platinum–iron nuggets from placer deposits include laurite, malanite, cuproiridsite, cooperite, hollingworthite, irarsite, moncheite, telluropalladinite and stibiopalladinite. The indications are that the platinum group minerals are of primary origin (CM 40.395-418).
The Bushveld Igneous Complex in South Africa is the world’s largest layered mafic–ultramafic intrusion. In the Lower Group chromitites of the complex the platinum group minerals enclosed within chromite grains consist mainly of laurite. Other important platinum group minerals include members of the laurite–erlichmanite series, the cooperite–braggite–vysotskite series and the malanite–cuprorhodsite series. platinum group element minerals of lesser abundance include sperrylite, geversite, stibiopalladinite, sudburyite and insizwaite, genkinite, moncheite, rustenburgite, tetraferroplatinum, native platinum, platarsite, hollingworthite and irarsite (CM 56.723-743).
The ultramafic pipes of Onverwacht and Tweefontein, in the Bushveld Complex, South Africa, contain small xenoliths of chromitite. Platinum-group minerals in the xenoliths include laurite, isoferroplatinum, ruthenium, cherepanovite, ruthenarsenite, rhodarsenide, palladodymite, palladoarsenide, stibiopalladinite, sudburyite, sperrylite and hollingworthite (CM 40.481-497).
In rivers draining the Easter Bushveld Complex, South Africa, stibiopalladinite or mertieite II occur as grains or intergrowths or as inclusions, occasionally together with atokite, in a platinum–iron alloy, tulameenite and gold grains. Inclusions of kotulskite in stibiopalladinite or mertieite II were observed in one specimen (CM 42.563-582).
The type locality is the Tweefontein Farm, Mokopane, Mogalakwena, Mogalakwena Local Municipality, Waterberg District Municipality, Limpopo, South Africa.
In the Lower Llandoverian metasedimentary series of the Prades Mountains, in southwestern Catalonia, Spain, native palladium and stibiopalladinite were found only in one sample as small platelets less than 2 microns in diameter, rimming the contact between palladian löllingite and arsenopyrite (CM 41.581-595).
At the Two Rivers platinum mine, Merensky Reef, Sekhukhune District, Limpopo, South Africa, primary minerals associated with chromitite stringers include orthopyroxene, clinopyroxene, plagioclase, and base-metal sulphides. Secondary silicates include tremolite, phlogopite, chlorite and serpentine. The most abundant base-metal sulphides are pyrrhotite, pentlandite and chalcopyrite. Platinum group minerals are dominated by maslovite, isoferroplatinum, braggite, cooperite and laurite, with minor michenerite, sperrylite, stibiopalladinite, geversite, platarsite and a variety of unnamed phases. There is a strong association of most platinum group minerals with pentlandite and chalcopyrite, but less so with pyrrhotite (CM 49.1385-1396).
At Tugidak Island, Kodiak Archipelago in Kodiak Island Borough, Alaska, United States, in black sand beach placers the major platinum mineral is isoferroplatinum, followed by minor tetraferroplatinum and tulameenite, and rare ferronickelplatinum. Inclusions of cuprorhodsite, malanite, cuproiridsite, laurite, erlichmanite, cooperite, braggite, bowieite, kashinite, miassite, hollingworthite, irarsite, sperrylite, stillwaterite, genkinite, stibiopalladinite, keithconnite, zvyagintsevite, and probable palladodymite and vincentite were identified. Most of the platinum group mineral inclusions are primary and were trapped by a growing crystal from a melt (CM 59.667-712)
At the Wet Legs deposit, Western Margin Duluth Complex, St. Louis county, Minnesota, USA, the main association consists of magmatic pyrrhotite, chalcopyrite, pentlandite and cubanite. Secondary bornite, covellite, yarrowite and digenite are found within variously altered troctolites. Several late stage arsenic-rich phases occur in the troctolites, including nickeline, maucherite, diarsenides in the system rammelsbergite-safflorite-löllingite, and sulfarsenides of the cobaltite-gersdorffite series. A three stage deposition is suggested, starting with the formation of nickeline, followed by diarsenides enriched in cobalt (below 600°C) and the late cobalt-rich sulfarsenides (between 550°C and 400°C) in the troctolitic host rock. The platinum-group minerals, sperrylite and stibiopalladinite, are either associated with primary magmatic sulphides, or hydrothermally altered patches of amphibole, chlorite, sericite, prehnite, carbonates and serpentine (CM 53.105-132).
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