Calaverite

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.

Physical and chemical 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.