Digenite

digenite

djurleite

chalcocite

bornite

Images

Formula: Cu1.8S
Sulphide, chalcocite group, high digenite (isometric digenite, stable above 73oC) forms a complete solid-solution series with berzelianite (Mindat); low digenite is trigonal.
Specific gravity: 5.546
Hardness: 2½ to 3
Streak: Greyish black
Colour: Grey to greyish black, turning bluish on exposure to air Mindat
Common impurities: A a small amount of iron always exists in digenite, and is necessary for its stability (AM 56.1889-1909).
Environments

Plutonic igneous environments
Pegmatites
Hydrothermal environments

Digenite occurs in hydrothermal copper deposits both as a primary and as a secondary mineral. 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).

Localities

The Two Mile and Three Mile deposits, Paddy's River, Paddys River District, Australian Capital Territory, Australia, are skarn deposits at the contact between granodiorite and volcanic rocks. digenite is a supergene sulphide that has been found as lumps up to 2 cm of massive digenite mixed with minor pyrite and chalcopyrite in quartz and quartz-chlorite material from the mine dumps (AJM 22.1.41).

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.

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).

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