Domeykite

minerals

koutekite

rammelsbergite

algodonite

Images
Formula: Cu3As
Arsenide
Specific gravity: 7.2 to 7.9
Hardness: 3 to 3½
Streak: black-grey
Colour: Tin white to steel grey
Solubility: Soluble in nitric acid (Dana)
Common impurities: Sb,S
Environments:

Hydrothermal environments

Domeykite is an arsenic mineral of hydrothermal origin, associated with copper (typically arsenian), silver and algodonite (HOM, Mindat).

Localities

At the Brunngraben district copper deposit, Flatschach, Knittelfeld, Styria, Austria, domeykite has been found with tenorite and also with koutekite and chalcocite (Mindat photos).

The type locality is the Los Algodones Mine, El Arrayan, La Serena, Elqui Province, Coquimbo, Chile.

At Běloves, Náchod District, Hradec Králové Region, Czech Republic, domeykite has been found with cuprite, olivenite, chrysocolla and malachite (Mindat photo).

At the Cashin Mine, La Sal Mining District, Montrose county, Colorado, USA, domeykite has been found with algodonite (Mindat photo).

At the Seneca mine, Mohawk, Keweenaw county, Michigan, USA, domeykite has been found with nickeline, calcite, quartz and rammelsbergite (Mindat photo).

Alteration

At 225oC cubic alpha domeykite decomposes to form algodonite (CJC 38.2477-2481).

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