Calaverite
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Calaverite | |
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General | |
Category | Telluride Mineral |
Chemical formula | AuTe2 |
Identification | |
Molecular Weight | 452.17 gm |
Color | Brass yellow to silver white |
Crystal habit | Massive to crystaline |
Crystal system | Monoclinic - Prismatic |
Cleavage | None |
Fracture | Uneven |
Tenacity | Brittle |
Mohs Scale hardness | 2.5-3 |
Luster | Metallic |
Optical Properties | Anisotropic |
Pleochroism | Weak |
Ultraviolet fluorescence | None |
Streak | Green to yellow grey |
Specific gravity | 9.1-9.3 |
Density | 9.1 - 9.4 g/cm3 |
Diaphaneity | opaque |
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 |
[edit] 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.
[edit] 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.
[edit] 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.
[edit] See also
[edit] 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