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
CategorySulfide mineral
Formula
(repeating unit)
RuS2
Strunz classification2.EB.05a
Crystal systemCubic
Crystal classDiploidal (m3)
H-M symbol: (P 2/m 3)
Space groupPa3
Unit cella = 5.61 Å; Z = 4
Structure

Crystal structure of Laurite
  S   Ru
Identification
ColorIron-black; white to gray or bluish in polished section
Crystal habitAs octahedral, cubic, and pyritohedral crystals or as rounded grains and inclusions
CleavagePerfect on {111}
FractureSubconchoidal
TenacityBrittle
Mohs scale hardness7.5
LusterMetallic
StreakDark gray
DiaphaneityOpaque
Specific gravity6.43
Density6.43 g/cm3 (Measured) 6.39 g/cm3 (Calculated)
Optical propertiesIsotropic 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

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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

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  1. ^ a b 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. ^ a b c 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.