Laurite

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 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 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]

References

1. Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Laurite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 14 March 2022.
2. "Laurite". Mindat.org .
3. "Laurite Mineral Data". Webmineral.com.
4. Cocco, R.A.; Tatarchuk, B.J. (1989). "Effects of presulfidization on the selectivity and surface structure of ruthenium catalysts" . Langmuir. 5 (6): 1309–1315. doi:10.1021/la00090a005 . Retrieved 20 June 2022.
5. Chianelli, R. R.; Berhault, G.; Raybaud, P.; Kasztelan, S.; Hafner, J.; Toulhoat, H. (2002). "Periodic Trends in Hydrodesulfurization: in Support of the Sabatier Principle". Appl. Catal., A. 227 (1–2): 83–96. doi:10.1016/S0926-860X(01)00924-3.