Formula: Pd2As
Arsenide of palladium
Specific gravity: 11.3 calculated
Colour: Brownish gray with a bluish tint in reflected light

Igneous environments
Placer deposits


At the type locality, the Miass River, Chelyabinsk Oblast, Russia, palladodymite occurs in platinum placers derived from ultra-basic rocks in a small fluvial placer deposit. It is found as inclusions, up to 30 × 70 μm, in native ruthenium. Other associated minerals include isoferroplatinum, cherepanovite, irarsite, hongshiite, sperrylite, tulameenite and unnamed IrAsTe (AM 85.876, HOM).

The Onverwacht and Tweefontein ultramafic pipes, eastern Bushveld Complex, in South Africa, contain small xenoliths of chromitite that consist of polyphase grains made up of:
(a) laurite along with unknown Ir–Ni–Fe sulphides and base-metal sulphides,
(b) abundant alloys (isoferroplatinum, ruthenium) and Rh–Pd–Ru arsenides (cherepanovite, ruthenarsenite, rhodarsenide, and palladodymite or palladoarsenide, with accessory laurite and palladium antimonides (stibiopalladinite or sudburyite), included both in fresh chromite and in interstitial olivine, and
(c) relatively large grains of sperrylite and hollingworthite with minor laurite associated with the altered portions of the chromitite host (CM 40.2.481-497).

In Umsweswe River sediment, Zimbabwe, palladodymite occurs with palladium- and rhodium-bearing platinum (HOM).

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