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	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	[1][2][3]

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] The sulfur is present as the disulfide ion, S2−2, so the ruthenium is in the Ru(II) oxidation state.^[4]

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]

Synthetic RuS₂ is a highly active catalyst for hydrodesulfurization.^[5]