Alabandite

Alabandite

Group of octahedral alabandite crystals partially coated with pink rhodochrosite, from Uchucchacua Mine, Oyon, Lima, Peru (size: 60 mm x 59 mm x 46 mm, 204 g)
General
Category Sulfide mineral
Formula
(repeating unit)		 MnS
Strunz classification 2.CD.10 (10 ed)
II/C.15-30 (8 ed)
Dana classification 2.8.1.4
Crystal system Cubic
Crystal class Hexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space group Fm3m
Unit cell a = 5.2236 Å; Z = 4
Identification
Color black, steelgray, brownish-black
Crystal habit mostly massive or granular; cubic or octahedral crystals to 1 cm
Twinning Lamellar || {111}
Cleavage Perfect on {100}
Fracture Irregular, uneven
Tenacity Brittle
Mohs scale hardness 3.5 to 4
Luster Sub-metallic
Streak Green
Diaphaneity Opaque, translucent in thin fragments
Specific gravity 4.053
Optical properties Isotropic
Refractive index n = 2.70
References [1][2]

Alabandite or alabandine is a rarely occurring manganese sulfide mineral. It crystallizes in the cubic crystal system with the chemical composition Mn2+S and develops commonly massive to granular aggregates, but rarely also cubic or octahedral crystals to 1 cm.

Etymology and History

Alabandite was first described in 1784 by Franz-Joseph Müller von Reichenstein.[3] The mineral name is derived from its supposed discovery locality at Alabanda (Aïdin) in Turkey.[2]

Occurrence

Alabandite forms in epithermal polymetallic sulfide veins and low-temperature manganese deposits. It occurs with acanthite, calcite, chalcopyrite, galena, pyrite, quartz, rhodochrosite, rhodonite, sphalerite and native tellurium. Sometimes it was found in meteorites.[1]

Localities are several areas in Antarctica, Argentina, Armenia, Australia, Bolivia, Brazil, Bulgaria, Canada, China, Czech Republic, Finland, France, Germany, Ghana, Greece, Greenland, India, Italy, Japan, Kyrgyzstan, Mexico, New Zealand, Norway, Peru, Poland, Romania, Russia, Slovakia, South Africa, South Korea, Sweden, Switzerland, Taiwan, Tanzania, the United Kingdom, the US, Uzbekistan and Yemen. Altogether at present time approximately 220 discovery sites are registered.

Crystal structure

Alabandite crystallizes in the cubic crystal system in the space group Fm3m with the lattice parameter a = 5.22 Å[4] and four formula units per unit cell.[1]

See also

References

  1. 1 2 3 Handbook of Mineralogy
  2. 1 2 Mindat.org
  3. ↑ www.mineral.hermuz.hu - A Kárpát-övezetben felfedezett ásványok
  4. ↑ American Mineralogist Crystal Structure Database - Alabandite (1991)
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