Digenite

sulphide

hydrothermal

Formula: Cu1.8S
Sulphide, chalcocite group, high digenite [cubic, high-temperature digenite] forms a complete solid-solution series with berzelianite (Mindat).
Specific gravity: 5.546
Hardness: 2½ to 3
Streak: Greyish black
Colour: Grey to greyish black, turning bluish on exposure to air Mindat
Digenite undergoes a rapidly reversible and non-quenchable transformation between 60 and 65oC (AM43.228-242).
Environments

Plutonic igneous environments
Pegmatites
Hydrothermal environments

Digenite occurs in hydrothermal copper deposits of primary and secondary origin. It has been reported from mafic intrusives, as an exhalation product, and in pegmatites (Webmin, HOM). Associated minerals include chalcocite, djurleite, bornite, chalcopyrite and pyrite (HOM, Mindat).

At the Sainte Lucie mine, Lazere, France, digenite occurs as microscopic pseudomorphs after galena (MinRec 42.1.14).

The type locality is the copper slate deposits, Sangerhausen, Saxony-Anhalt, Germany (Mindat).

At the Leonard mine, Butte, Montana, USA, digenite occurs with bornite and pyrite (AM 56.1889-1909).

At Balmat, Saint Lawrence county, New York, USA, digenite is associated with magnetite (AM 41.6.536).

Common impurities: A a small amount of iron always exists in digenite, and is necessary for its stability (AM 56.1889-1909).

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