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Calaverite



Calaverite
CategoryTelluride Mineral
Chemical formulaAuTe2
Identification
Molecular Weight452.17 gm
ColorBrass yellow to silver white
Crystal habitMassive to crystaline
Crystal systemMonoclinic - Prismatic
CleavageNone
FractureUneven
TenacityBrittle
Mohs Scale hardness2.5-3
LusterMetallic
Optical PropertiesAnisotropic
PleochroismWeak
Ultraviolet fluorescenceNone
StreakGreen to yellow grey
Specific gravity9.1-9.3
Density9.1 - 9.4 g/cm3
Diaphaneityopaque
References[1] [2] [3]

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.

Contents

Physical properites

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 properites

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.

Occurences

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.

See also

References

  1. ^ http://www.mindat.org/min-852.html
  2. ^ http://webmineral.com/data/Calaverite.shtml
  3. ^ http://mineral.galleries.com/minerals/sulfides/calaveri/calaveri.htm
  • 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
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Calaverite". A list of authors is available in Wikipedia.
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