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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.
Crystal System: Isometric (high digenite) or trigonal (low digenite)
Specific gravity: 5.546 measured, 5.706 calculated
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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