Calaverite
| Calaverite | |
|---|---|
 | |
| 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.
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
- 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
Source: adapted by the editor from Wikipedia, the free encyclopedia; from the article "Calaverite". Image Credit.
