Trogtalite

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.[2] It often occurs as grains. It was thought to be dimorphous with hastite, but this was discredited in 2009.[3] Hastite turned out to be the iron selenide mineral ferroselite.[4] It forms a solid solution series with krut'aite.

Trogtalite
Piece of oosterboschite with cuprosklodowskite, quartz, and brown oxidized trogtalite from the Musonoi mine. From the Howard Belsky collection.
General
CategorySelenide minerals
Formula
(repeating unit)		CoSe2
IMA symbolTrg[1]
Strunz classification2.EB.05a
Dana classification2.12.1.5
Crystal systemCubic
Crystal classDiploidal (m3)
H-M symbol: (2/m 3)
Space groupPa3
Identification
ColorRose-violet
Crystal habitIrregular grains
Mohs scale hardness3.5-5.5
LusterMetallic
DiaphaneityOpaque
Density7.12 (calculated) 7.09 (synthetic)
PleochroismNone
Ultraviolet fluorescenceNone
SolubilityInsoluble
Common impuritiesCu, Pd
References

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, native selenium, gold, and oosterboschite.[5]

See also

References
  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. "Trogtalite: Trogtalite mineral information and data". www.mindat.org. Retrieved 2016-10-20.
  3. 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 (4): 969–976. doi:10.3749/canmin.47.4.969.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. "Hastite: Hastite mineral information and data". www.mindat.org. Retrieved 2016-10-20.
  5. "Handbook of mineralogy, trogtalite" (PDF).
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