Empressite

minerals

petzite

hessite

rickardite

Formula: AgTe
Telluride
Specific gravity: 7.61
Hardness: 3 to 3½
Streak: Grey-black to black
Colour: light bronze
Solubility: Readily soluble in hot dilute nitric acid (AM 36.458-469)
Common impurities: Pb,Cu,Fe,S
Environments

Hydrothermal environments

Empressite occurs in low temperature gold-poor hydrothermal vein deposits, associated with hessite, petzite, pyrite and rickardite (Mindat).

Localities

At Pitman, Canada, empressite is associated with gold, tellurium, hessite, petzite and rickardite (HOM).

At Tombstone, Arizona, USA, empressite is associated with pyrite and rodalquilarite (HOM).

At the type locality, the Empress Josephine Mine, Bonanza, Saguache county, Colorado, USA, empressite occured as euhedral prismatic grains to 400 microns containing no inclusions or intergrowths with other minerals (AM 89.1043-1047). A second specimen from the type locality consists of a massive aggregate of empressite with a small amount of galena, altaite, and stutzite on one corner. Much of the surface is covered by a fine grained aggregate of muscovite variety sericite containing small pyrite crystals (AM 49.325-328). Other associated minerals here include tellurium, sylvanite, petzite, hessite and rickardite (HOM).

Alteration

Empressite decomposes to Ag5Te3 plus Te at 210oC (AM 49.325-328).

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