Digenite - Encyclopedia
Class : Sulfides and sulfosalts
Subclass : Sulfides
Crystal system : Trigonal
Chemistry : Cu9S5
Rarity : Uncommon
Digenite is a copper sulfide of essentially secondary origin. It comes from the alteration of chalcocite, chalcopyrite and bornite, and systematically accompanies secondary covellite in the oxidation and cemantation zones of copper deposits. Primary digenite is much rarer, known in basic intrusions and pegmatites. Its name comes from the Greek digenês (of two sexes or genders) to translate the supposed presence of two types of ions (copper and cupric), its name would also be an allusion to the error made in the past of believing it to be composed of a mixture of two sulphides (chalcocite and covellite). Digenite is mostly massive, but can sometimes form deformed cubo-octahedrons up to 6 cm, blue-black to black in color. It is a fairly minor copper ore.
Main photo : 6 cm digenite from Leonard Mine, Butte, Montana, USA - Smithsonian Collection © Kelly Nash
Digenite in the World
Twinning
No twin known for this mineral species.
Fakes and treatments
No fakes listed for this mineral species.
Hardness : 2.5 to 3
Density : 5.54
Fracture : Conchoidal
Streak : Gray-black
TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None
Solubility : Nitric acid
Magnetism : None
Radioactivity : None