Stromeyerite

minerals

bornite

tennantite

polybasite

Formula: CuAgS
Sulphide
Specific gravity: 6.2 to 6.3
Hardness: 2½ to 3
Streak: Steel grey
Colour: Blue grey, dark blue, dark steel grey, or steel grey
Common impurities: Fe
Environments:

Hydrothermal environments

Stromeyerite is an accessory mineral in silver-copper deposits. It occurs in the supergene enriched zone of hydrothermal veins, formed most commonly by secondary processes, although it also forms as a primary mineral. Associated minerals include freibergite, bornite, chalcopyrite and galena (HOM, Dana, Mindat).

Localities

At the type locality, the Zmeinogorsk mine, Zmeevka Stream, Korbalikha River, Alei River Basin, Altai Krai, Russia, stromeyerite occurs in copper and silver bearing veins, where silver replaces copper in bornite (Mindat).

At Yellow Pine, Sugarloaf District, Boulder county, Colorado, USA, a bed of stromeyerite overlying a bed of sphalerite and galena has been reported, and also stromeyerite intergrown with stephanite in tennantite - tetrahdrite (R&M 87.4.304-336).

At the Red Mountain District, Ouray county, Colorado, USA, the ore deposits take the form of chimneys or breccia pipes usually several hundred feet across and cropping out as irregular knobs of silicified rock. They penetrate the earth to a depth from several hundred to a thousand or more feet. Pipes consist of an intensely shattered, silicified, and hydrothermally altered rock. The typical ore mineral assemblage of the chimneys includes pyrite, enargite, chalcopyrite, chalcocite, covellite, bornite, sphalerite and galena. Additionally, tetrahedrite, tennantite, polybasite, pearceite, pyrargyrite, proustite, stromeyerite, and free gold are important in some pipes (R&M 87.4.304-336).

At the Yankee Girl mine, Poughkeepsie Gulch, Red Mountain Mining District, San Juan county, Colorado, USA, stromeyerite occurs with chalcopyrite (R&M 87.4.304-336).

At the Baltic Mine, Baltic, Houghton county, Michigan, USA, samples from the mine dump revealed crude wires of native silver associated with chalcocite, quartz, and minor baryte, together with small patches of stromeyerite. It seems possible that silver released by stromeyerite alteration supported the growth of these wire silvers (R&M 86-2.174).

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