Palladodymite
Palladodymite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Pd₂As.
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Barringerite structural group.
Key properties: Mohs hardness 5; specific gravity 11.3.
IMA symbol Pdd, IMA status: approved, named in 1997.
Found in a small fluvial placer deposit (Russia, Zimbabwe); in chromitite xenoliths in ultramafic pipes (South Africa).
It is found associated with Ruthenium, isoferroplatinum, cherepanovite, irarsite, hongshiite, sperrylite, tulameenite (Russia); Pd- and Rh-bearing platinum (Zimbabwe).
Alludes to the chemical composition and relationship to the Rh analog, rhodarsenide (palladium and dymos, the latter the Greek for twin).