Trogtalite

Trogtalite
Piece of oosterboschite with cuprosklodowskite, quartz, and brown oxidized trogtalite from the Musonoi mine. From the Howard Belsky collection.
General
Category Selenide minerals
Formula
(repeating unit)		 CoSe2
Strunz classification 2.EB.05a
Dana classification 2.12.1.5
Crystal system Cubic
Crystal class Diploidal (m3)
H-M symbol: (2/m 3)
Space group Pa3
Identification
Color Rose-violet
Crystal habit Irregular grains
Mohs scale hardness 3.5-5.5
Luster Metallic
Diaphaneity Opaque
Density 7.12 (calculated) 7.09 (synthetic)
Pleochroism None
Ultraviolet fluorescence None
Solubility Insoluble
Common impurities Cu, Pd
References

Trogtalite is a rare selenide mineral with the formula CoSe2. It crystallizes in the cubic system and is part of the pyrite group, consisting of Co2+ and Se22− ions. It has a rose-violet colour and its crystals are opaque.[1] It often occurs as grains. It was thought to be dimorphous with hastite, but this was discredited in 2009.[2] Hastite turned out to be the iron selenide mineral ferroselite.[3] It forms a solid solution series with krut'aite.

Occurrence

Trogtalite was first found in 1955 in Trogtal quarry, Lautenthal, Harz Mountains, Germany, after which it was also named. It often occurs intergrown with clausthalite grains at this locality. It has also been found in the Musonoi Cu–Co mine, Kolwezi, Katanga Province, Congo and in Argentina, in Tuminico, Sierra de Cacho, and in Los Llantenes, La Rioja Province. It is often found together with clausthalite, ferroselite, bornhardtite, selenium, gold, and oosterboschite.[4]

See also

References

  1. ↑ "Trogtalite: Trogtalite mineral information and data". www.mindat.org. Retrieved 2016-10-20.
  2. ↑ Frank N. Keutsch, Hans-Jürgen Förster, Chris J. Stanley, Dieter Rhede (September 11, 2009). "The discreditation of hastite, the orthorhombic dimorph of CoSe2, and observations on trogtalite, cubic CoSe2, from the type locality". Canadian mineralogist. 47: 969–976.
  3. ↑ "Hastite: Hastite mineral information and data". www.mindat.org. Retrieved 2016-10-20.
  4. ↑ "Handbook of mineralogy, trogtalite" (PDF).
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