Hauerite

Hauerite
General
Category Sulfide mineral, pyrite group
Formula
(repeating unit)		 MnS2
Strunz classification 2.EB.05a
Crystal system Cubic
Crystal class Diploidal (m3)
H–M Symbol: (2/m 3)
Space group Pa3
Unit cell a = 6.107 Å; Z = 4
Identification
Formula mass 119.07 g/mol
Color Reddish brown or brownish black
Crystal habit Octahedral crystals and globular aggregates
Cleavage {100} Perfect, {010} Perfect, Perfect on {001}
Fracture Uneven to subconchoidal
Tenacity Brittle
Mohs scale hardness 4
Luster Metallic-adamantine
Streak Reddish brown
Diaphaneity Opaque to subtranslucent
Specific gravity 3.463
Optical properties Isotropic
Refractive index n = 2.69
References [1][2][3]

Hauerite is a manganese sulfide mineral with the chemical formula MnS2. It forms reddish brown or black octahedral crystals with the pyrite structure and it is usually found associated with the sulfides of other transition metals such as rambergite. It occurs in low temperature, sulfur rich environments associated with solfataras and salt deposits in association with native sulfur, realgar, gypsum and calcite.[1]

It was discovered in Austro-Hungarian Monarchy near Banska Bystrica in what is now Slovakia in 1846 and named after the Austrian geologists, Joseph Ritter von Hauer (1778–1863) and Franz Ritter von Hauer (1822–1899).[1][3]

Under high pressure conditions (P>11 GPa), Hauerite undergoes a large collapse in unit cell volume (22 %) driven by a spin-state transition.[4]

References

  1. 1 2 3 Handbook of Mineralogy
  2. ↑ Webmineral
  3. 1 2 Mindat.org
  4. ↑ Kimber, S.A.J., et al., Giant pressure-induced volume collapse in the pyrite mineral MnS2, PNAS, April 8, 2014, vol. 111, no. 14, pp. 5106-5110
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