Laurite
Laurite | |
---|---|
General | |
Category | Sulfide mineral |
Formula (repeating unit) | RuS2 |
Strunz classification | 2.EB.05a |
Crystal system | Cubic |
Crystal class |
Diploidal (m3) H-M symbol: (2/m 3) |
Space group | Pa3 |
Unit cell | a = 5.61 Å; Z = 4 |
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 |
Optical properties | Isotropic and opaque |
References | [1][2][3] |
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 rare, it occurs in many parts of the world.
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.[2]
Discovery and occurrence
It was discovered in 1866 in Borneo, Malaysia and named for Laurie, the wife of Charles A. Joy, an American chemist.[2] It occurs in ultramafic magmatic cumulate deposits and sedimentary placer deposits derived from them. It occurs associated with cooperite, braggite, sperrylite, other minerals of the platinum group elements and chromite.[1]
References
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