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Formula: RuAsS
Sulphide, arsenopyrite group,
ruthenium- and arsenic-
bearing mineral
Crystal System: Monoclinic
Specific gravity: 7.08 calculated
Hardness: 6 to 7
Streak: Greyish black
Colour: Dark lead-grey
Luminescence:
Solubility: Insoluble in 1:1 hydrochloric acid
Magnetism: Non-magnetic
Common impurities: Os,Ir,Pt
Environments
Localities
Styria, Austria: the Kraubath and Hochgrössen ultramafic massifs, situated within
the province of Styria, are parts of a strongly deformed, metamorphosed and dismembered
ophiolite complex; they are composed of metamorphosed, foliated
harzburgite and dunite, with
numerous bodies of chromitite of generally less than 0.5 m thick. Unaltered
and altered podiform chromitites occur both at Kraubath and at Hochgrössen.
The platinum group mineral assemblage in the unaltered podiform ores is dominated by
laurite. Sperrylite is the most abundant
platinum group mineral in the altered
chromitite, whereas minerals of the
laurite–erlichmanite series are
subordinate. At Kraubath, osmium-bearing
platinum group minerals (laurite,
erlichmanite, ruarsite and an
osmium–iridium alloy) occur as single grains
and as complex polyphase assemblages
(CM 41.331-352).
At the type locality, the Anduo Cr deposit, Amdo county, Nagchu Prefecture, Tibet, China, ruarsite occurs as
irregular grains or as aggregates (100-150 µm) in heavy mineral concentrates, in
chromium ore derived from an Alpine-type
ultramafic and in placers derived from the weathered
ultramafics. Associated minerals include
iridosmine, rutheniridosmine,
ruthenosmiridium, iridarsenite,
irarsite, ruthenarsenite,
rutile, osmium,
sperrylite, laurite,
chromian spinel,
pyrite, pyrrhotite,
löllingite, magnetite,
chalcopyrite, molybdenite,
galena, millerite,
ilmenite, gold,
garnet, chromite,
chlorite, chalcopyrite and
anduoite
(HOM, Mindat).
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