Krennerite

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Krennerite
Krennerite-118304.jpg
Krennerite from the Cresson Mine, Cripple Creek, Colorado. About 5 mm.
General
Category Telluride mineral
Formula
(repeating unit)
AuTe2
Strunz classification 02.EA.15
Identification
Formula mass 453.2
Color White to blackish yellow
Crystal habit Massive to crystalline
Crystal system Orthorhombic - Pyramidal
Cleavage Perfect
Fracture Conchoidal
Mohs scale hardness 2.5
Luster Metallic
Streak greenish grey
Diaphaneity opaque
Density 8.53
Optical properties Anisotrophic
Pleochroism weak
Ultraviolet fluorescence None
References [1][2]

Krennerite is an orthorhombic gold telluride mineral which can contain a relatively small amount of silver in the structure. The formula is AuTe2 varying to (Au0.8,Ag0.2)Te2. Both of the chemically similar gold-silver tellurides, calaverite and sylvanite, are in the monoclinic crystal system, whereas krennerite is orthorhombic.

The color varies from silver-white to brass-yellow. It has a specific gravity of 8.53 and a hardness of 2.5. It occurs in high temperature, hydrothermal environments.

Krennerite was discovered in 1878 in Sacaramb, Romania, and first described by the Hungarian mineralogist Joseph Krenner (1839–1920).

See also[edit]

References[edit]

Krennerite in a quartz vein, Cresson Mine, Cripple Creek, Colorado. Specimen size 3.0 x 2.7 x 2.5 cm. See infobox for detail photo.