Calaverite

Infobox mineral
name = Calaverite
category = Telluride Mineral
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formula = AuTe₂
molweight = 452.17 gm
color = Brass yellow to silver white
habit = Bladed and slender striated prisms, also massive granular
system = Monoclinic - Prismatic
twinning = Common on [110]
cleavage = None
fracture = Uneven to subconchoidal
tenacity = Brittle
mohs = 2.5-3
luster = Metallic
polish =
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opticalprop = Anisotropic
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dispersion =
pleochroism = Weak
fluorescence= None
absorption =
streak = Green to yellow grey
gravity = 9.1-9.3
density =
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fusibility =
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solubility =
diaphaneity = opaque
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references = [ [http://www.mindat.org/min-852.html Calaverite: Calaverite mineral information and data ] ] [ [http://webmineral.com/data/Calaverite.shtml Calaverite Mineral Data ] ] [ [http://mineral.galleries.com/minerals/sulfides/calaveri/calaveri.htm CALAVERITE (Gold Telluride) ] ]

Calaverite, or gold telluride, is an uncommon telluride of gold; it is a metallic mineral. It was first discovered in Calaveras County, California in 1861. Its chemical formula is AuTe₂. Its color may range from a silvery white to a brassy yellow. It is closely related to the gold - silver telluride sylvanite. Another mineral containing AuTe₂ is krennerite. Calaverite represents a minor ore of gold and tellurium.

Physical properties

Calaverite occurs as monoclinic crystals, which do not possess cleavage planes. It has a specific gravity of 9.35 and a hardness of 2.5.

Chemical properties

Calaverite can be dissolved in concentrated sulfuric acid. In hot sulfuric acid the mineral dissolves, leaving a spongy mass of gold in a red solution of tellurium.

Occurrence

Calaverite occurrences include Cripple Creek, Colorado; Calaveras County, California, USA (from where it gets its name); Nagyag, Romania; Kirkland Lake Gold District, Ontario; Rouyn District, Quebec; and Kalgoorlie, Australia.

In the Kalgoorlie gold rush of the 1890s, large amounts of calaverite were mistaken for fool's gold, and were discarded. The mineral deposits were used as a building material, and for the filling of potholes and ruts. Several years later, the nature of the mineral was identified, leading to a minor gold rush to excavate the streets.

ee also

*List of minerals

References

*D. M. Chizhikov, V. P. Shchastlivyi, 1966, "Tellurium and Tellurides", Nauka Publishing, Moscow
*Klein, Cornelis and Hurlbut, Cornelius S., 1985, "Manual of Mineralogy" 20th ed., p. 289, Wiley, ISBN 0-471-80580-7
*Fortey, Richard, 2004, "The Earth", Harper Collins