Calaverite

Calaverite
Platy calaverite crystals on matrix from the Cripple Creek District (size: 6 x 5 x 3.5 cm)
General
CategoryTelluride mineral
Formula
(repeating unit)
AuTe2
IMA symbolClv[1]
Strunz classification2.EA.10
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/m
Unit cella = 7.19 Å, b = 4.4 Å,
c = 5.08 Å; β = 90.3°; Z = 2
Identification
Formula mass452.17 g/mol
ColorBrass yellow to silver white
Crystal habitBladed and slender striated prisms, also massive granular
TwinningCommon on [110]
CleavageNone
FractureUneven to subconchoidal
TenacityBrittle
Mohs scale hardness2.5–3
LusterMetallic
StreakGreen to yellow grey
DiaphaneityOpaque
Specific gravity9.1–9.3
Optical propertiesAnisotropic
PleochroismWeak
Ultraviolet fluorescenceNone
References[2][3][4][5]

Calaverite, or gold telluride, is an uncommon telluride of gold, a metallic mineral with the chemical formula AuTe2, with approximately 3% of the gold replaced by silver. It was first discovered in Calaveras County, California in 1861, and was named for the county in 1868.

The mineral often has a metallic luster, and its color may range from a silvery white to a brassy yellow. It is closely related to the gold-silver telluride mineral sylvanite, which, however, contains significantly more silver. Another AuTe2 mineral (but with a quite different crystal structure) is krennerite. Calaverite and sylvanite represent the major telluride ores of gold, although such ores are minor sources of gold in general. As a major gold mineral found in Western Australia, calaverite played a major role in the 1890s gold rushes in that area.

  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. ^ Mineralienatlas
  3. ^ Calaverite, Mindat.org, retrieved 14 October 2023
  4. ^ Barthelmy, David (2014). "Calaverite Mineral Data". Webmineral.com. Retrieved 3 August 2022.
  5. ^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Calaverite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 3 August 2022.