Laurite

Laurite
General
Category Sulfide mineral
Formula
(repeating unit)
RuS2
Strunz classification 2.EB.05a
Crystal system Cubic
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
Crystal symmetry Isometric diploidal
H-M symbol: 2/m3
Space group: Pa3
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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