Laurite
Laurite is an opaque black, metallic ruthenium sulfide mineral with formula: RuS2. It crystallizes in the isometric system. It is in the pyrite structural group. Though it's been found in many localities worldwide, it is extremely rare.
| Laurite | |
|---|---|
| General | |
| Category | Sulfide mineral |
| Formula (repeating unit) | RuS2 |
| Strunz classification | 2.EB.05a |
| Crystal system | Cubic |
| Crystal class | Diploidal (m3) H-M symbol: (P 2/m 3) |
| Space group | Pa3 |
| Unit cell | a = 5.61 Å; Z = 4 |
| Structure | |
|
Crystal structure of Laurite S Ru | |
| Identification | |
| Color | Iron-black; white to gray or bluish in polished section |
| Crystal habit | As octahedral, cubic, and pyritohedral crystals or as rounded grains and inclusions |
| Cleavage | Perfect on {111} |
| Fracture | Subconchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 7.5 |
| Luster | Metallic |
| Streak | Dark gray |
| Diaphaneity | Opaque |
| Specific gravity | 6.43 |
| Density | 6.43 g/cm3 (Measured) 6.39 g/cm3 (Calculated) |
| Optical properties | Isotropic and opaque |
| References | |
Laurite has a Mohs hardness of 7.5 and a specific gravity of 6.43. It can contain osmium, rhodium, iridium, and iron substituting for the ruthenium. The sulfur is present as the disulfide ion, S2−2, so the ruthenium is in the Ru(II) oxidation state.
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