Sperrylite
| Sperrylite | |
|---|---|
 |
|
| General | |
| Category | Arsenide mineral Pyrite group |
|
Formula (repeating unit) |
PtAs2 |
| Strunz classification | 2.EB.05a |
| Crystal system | Isometric |
| Crystal class | Diploidal (m3) H-M symbol: (2/m 3) |
| Space group | Pa3 |
| Unit cell | a = 5.967 Å, Z = 4 |
| Identification | |
| Color | Tin white |
| Crystal habit | Well-formed finely crystalline, massive to reniform |
| Cleavage | Indistinct on {001} |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 6 - 7 |
| Luster | Metallic |
| Streak | Black |
| Specific gravity | 10.58 |
| References | |
Sperrylite is a platinum arsenide mineral with formula PtAs2 and is an opaque metallic tin white mineral which crystallizes in the isometric system with the pyrite group structure. It forms cubic, octahedral or pyritohedral crystals in addition to massive and reniform habits. It has a Mohs hardness of 6 - 7 and a very high specific gravity of 10.6.
It was discovered by Francis Louis Sperry, an American chemist, in 1889 at Sudbury.
The most important occurrence of sperrylite is in the nickel ore deposit of Sudbury Basin in Ontario, Canada. It also occurs in the layered igneous complex of the Bushveld region of South Africa and the Oktyabr'skoye copper-nickel deposit of the Eastern-Siberian Region, Russia.
Sperrylite is the most common platinum mineral, it generally occurs with a wide array of other unusual minerals, including cooperite [(Pt,Pd,Ni)S], laurite [RuS2], kotulskite [Pd(Te,Bi)], merenskyite [(Pd,Pt)(Te,Bi)2], iridium-osmium (Ir-Os) alloys, sudburyite [(Pd,Ni)Sb], omeiite [(Os,Ru)As2], testibiopalladite [PdTe(Sb,Te)], and niggliite [PtSn], to name a few. It does not readily decompose through normal weathering processes and, consequently, has been reported in widely scattered alluvial deposits.
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