Silvery metallic nugget of the extremely rare Rh and Ir minerals, cuprorhodsite and cuproiridsite, in an analyzed specimen by SEM/EDS by the former owner of the specimen (the Vandenbroucke Museum). fROM: Aldan Shield, Sakha Republic, Russian Federation. — Photo: David Hospital · CC BY-SA 4.0
Cuproiridsite
Cuproiridsite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Cu(Ir³⁺Ir⁴⁺)S₄.
It crystallizes in the cubic crystal system (space group Fd3m). It is a member of the Spinel structural group.
Key properties: specific gravity 7.24; Metallic. R: (400) —, (420) —, (440) —, (460) 35.0, (480) 34.4, (500) 34.0, (520) 34.0, (540) 33.6, (560) 33.4 luster.
IMA symbol Cir, IMA status: approved, named in 1984.
Found in alluvial deposits.
It is found associated with Isoferroplatinum, cuprorhodsite, malanite, osmium, iridosmine, platinum, laurite, erlichmanite, cherepanovite, kashinite, rhodian pentlandite, irarsite.
The name refers to copper, CUPRum, IRIDium, and Sulfur in the chemical composition.