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Formula: Pd5Sb2
Alloy of palladium and antimony,
arsenopalladinite group
Crystal System: Hexagonal
Specific gravity: 10.8 calculated
Hardness: 4 to 5
Streak: Black
Colour: Silver, white to steel-grey
Common impurities: Cu,Sn,As
Environments
Plutonic igneous environments
Placer deposits
Stibiopalladinite is an uncommon constituent of platinum deposits.
Associated minerals include braggite,
cooperite, mertieite,
sperrylite,
platinum-iron-copper-nickel
alloys, genkinite, platarsite,
chromite, chalcopyrite,
pentlandite, pyrrhotite,
geversite, gold and
violarite
(HOM).
Localities
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 (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 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 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 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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