Cooperite
Cooperite is a grey mineral consisting of platinum sulfide (PtS), generally in combinations with sulfides of other elements such as palladium and nickel (PdS and NiS). Its general formula is (Pt,Pd,Ni)S. It is a dimorph of braggite.
It is mined as an ore of platinum and platinum group metals such as palladium. It occurs in South Africa in minable quantities and a small old mine near Mount Washington on Vancouver Island.