Algodonite

algodonite

koutekite

domeykite

novakite

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Formula: Cu1-xAsx (x ~ 0.15)
Arsenide
Crystal System: Hexagonal
Specific gravity: 8.38 measured, 8.72 calculated
Hardness: 4
Colour: Steel-grey to silver-white, tarnishes dull on exposure
Common impurities: Ag
Environments:

Hydrothermal environments

Algodonite occurs in hydrothermal deposits intimately associated with other copper arsenides. Common associates include copper (typically arsenic-rich), silver, domeykite and koutekite (HOM, Mindat).

Localities

At the Cashin mine, Montrose county, Colorado, USA, novákite is associated with algodonite, koutekite, djurleite and domeykite (HOM).

At Painsdale, Michigan, USA, copper arsenide specimens have been found to contain crystals of algodonite. Many crystals occur as parallel overgrowths on ill-formed crystals of arsenic-rich copper. The masses of arsenides in which the algodonite occurs are rich in copper near the matrix, and the arsenic content appears to increase in the centres of the masses. The good crystals line pockets in the arsenides; algodonite is interstitial to quartz and calcite and so does not form well developed crystals in the matrix (AM 48.421-422).

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