| Cooperite | |
|---|---|
 Cooperite specimen from Tulameen River, Princeton, British Columbia, Canada | |
| General | |
| Category | Mineral |
| Formula (repeating unit) | PtS (also PdS, NiS) |
| IMA symbol | Cpe[1] |
| Strunz classification | 2.CC.35b |
| Dana classification | 2.8.5.1 |
| Crystal system | Tetragonal |
| Crystal class | Tetragonal - Ditetragonal dipyramidal |
| Space group | P42/mmc (No. 131) |
| Unit cell | 73.57 ų (Calculated from Unit Cell) |
| Identification | |
| Colour | Steel gray |
| Twinning | Occasional |
| Fracture | Conchoidal |
| Mohs scale hardness | 4–5 |
| Luster | Metallic |
| Diaphaneity | Opaque |
| Specific gravity | 9.5 |
| Density | 9.5 g/cm3 (Measured), 10.2 g/cm3 (Calculated) |
| Pleochroism | Visible: white to creamy white or bluish white |
| Major varieties | |
| Form | Distorted crystal fragments, irregular grains to 1.5mm |
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.[2]
It is mined as an ore of platinum and platinum group metals such as palladium. It occurs in South Africa in minable quantities and an old mine near Mount Washington on Vancouver Island.[3]
It was first described in 1928 for occurrences in the Bushveld Igneous Complex and named after South African metallurgist Richard A. Cooper who first characterized it.[2][4]