- Cobaltite
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Cobaltite 
Cobaltite from SwedenGeneral Category Sulfosalt mineral Chemical formula CoAsS Strunz classification 02.EB.25 Crystal symmetry Orthorhombic mm2 Unit cell a = 5.582 Å, b = 5.582 Å, c = 5.582 Å; Z = 4 Identification Color Reddish silver white, violet steel gray to black Crystal habit Granular to massive, rarely as striated crystals Crystal system Orthorhombic, pseudocubic. Twinning About [111] creating pseudo-cubic forms and striations Cleavage Perfect on {001} Fracture Uneven Tenacity Brittle Mohs scale hardness 5.5 Luster Metallic Streak Grayish-black Diaphaneity Opaque Density 6.33 g/cm³ References [1][2] Cobaltite is a sulfosalt mineral composed of cobalt, arsenic and sulfur, CoAsS. It contains up to 10 percent iron and variable amounts of nickel.[3] Structurally it resembles pyrite (FeS2) with one of the sulfur atoms replaced by an arsenic atom.
Although rare it is mined as a significant source of the strategically important metal cobalt. Secondary weathering incrustations of erythrite, hydrated cobalt arsenate, are common.
The name is from the German, Kobold, "underground spirit" in allusion to the "refusal" of cobaltiferous ores to smelt as they are expected to.[4]
It occurs in high temperature hydrothermal deposits and contact metamorphic rocks. It occurs in association with magnetite, sphalerite, chalcopyrite, skutterudite, allanite, zoisite, scapolite, titanite, calcite along with numerous other Co–Ni sulfides and arsenides.[1] It was described as early as 1832 and its type locality is Cobalt, Ontario.[2]
It is found chiefly in Sweden, Norway, Germany, Cornwall, England, Canada, Australia, Democratic Republic of the Congo and Morocco.[1][3]
References
- ^ a b c http://rruff.geo.arizona.edu/doclib/hom/cobaltite.pdf Mineral Handbook
- ^ a b http://webmineral.com/data/Cobaltite.shtml Webmineral data
- ^ a b Klein, Cornelus and Cornrlius Hurlbut, 1996, Manual of Mineralogy, 20th ed., Wiley, p.288, ISBN 0-471-80580-7
- ^ http://www.mindat.org/min-1093.html Mindat
External links
Chisholm, Hugh, ed (1911). "Cobaltite". Encyclopædia Britannica (11th ed.). Cambridge University Press.
Cubic Cobaltite, 1.6 x 1.4 x 1.1 cm, Brazil Lake Occurrence (Elizabeth Lake Mine), Sudbury District, Ontario, Canada
Categories:- Cobalt minerals
- Iron minerals
- Arsenic minerals
- Sulfosalt minerals
- Orthorhombic minerals
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