Orcelite

orcelite

pentlandite

maucherite

breithauptite

Images

Formula: Ni5-xAs2 (x = 0.23)
Arsenide
Specific gravity: 6.5 to 7.25
Colour: Rose-bronze
Common impurities: Fe,S,Si,Mg,H2O
Environments

Plutonic igneous environments
Metamorphic environments

Particles of orcelite from partly serpentinised peridotite from different mantle-derived ultramafic bodies from around the world have been studied. The orcelite is associated in serpentine veins with a copper-nickel rich, sulphide-poor assemblage. It crystallised at a low temperatue of less than 450oC during serpentinisation, substituting for a primary nickeline-maucherite assemblage as the result of the release of nickel by the serpentinising solutions. Associated minerals include pentlandite, heazlewoodite, millerite, parkerite, maucherite, breithauptite, magnetite, nickel, copper, chalcopyrite, chalcocite and galena (CM 22.553-560, HOM).

Localities

At the type locality, the Tiébaghi Cr mine, Tiébaghi Massif, Koumac Commune, Northern Province, New Caledonia, France, orcelite occurs in serpentinised harzburgite as inclusions in pentlandite and as rims on maucherite (AM 45.753-754, Mindat).

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