CALAVERITE

    Class : Sulfides and sulfosalts
    Subclass : Tellurides
    Crystal system : Monoclinic
    Chemistry : AuTe2
    Rarity : Rare

Calaverite is a rare primary telluride of epithermal gold deposits, in which it coexists with native gold, other tellurides (hessite, altaite, krennerite, etc...) as well as base metal sulfides. It owes its name to its discovery location : the Stanislaus mine in Calaveras County (California). Its crystals are rare, flattened lamellar, or short to elongated prismatic, slender according to [010]. This very fragile gold telluride has a bright metallic luster, a brass yellow to silver white color, but no cleavage. It is a very incidentalore of gold.

Main photo : Calaverite from Cresson Mine, Colorado, USA © Jason B. Smith

Calaverite from Ajax Mine, Colorado, USA © Carsten Slotta
4 cm calaverite from Cripple Creek, Colorado, USA © John R. Montgomery
Calaverite from Cripple Creek, Colorado, USA © Christophe Boutry
Calaverite from Portland Mine, Colorado, USA © Carsten Slotta

Calaverite in the World

The best occurrence in the world is the Cresson mine (Cripple Creek, Colorado) where a cavity measuring 12 m x 6 m x 5 m was discovered in 1914, lined with gold telluride crystals and native gold, including superb centimeter-sized individuals of calaverite (up to 15mm). More recently this deposit provided crystals measuring more than 4 cm ! Calaverite is also known in millimeter crystals in gold mines in California (especially in Calaveras County), and in various mines in Canada, Romania, Australia, China and the Fiji Islands.

Calaverite in France

is not present in the French underground.

Twinning

Twins are known and common on {110}, less frequent on {031} and {111}.

Fakes and treatments

No fake identified for this mineral species.


Hardness : 2.5 to 3
Density : 9.1 to 9.4
Fracture : Irregular
Streak : Greenish to yellowish gray

TP : Opaque
RI : -
Birefringence : 0
Optical character : None
Pleochroism : None
Fluorescence : None

Solubility : Nitric acid, sulfuric acid

Magnetism : None
Radioactivity : None