Mass rich in dark gray digenite, intergrown with pyrite and chalcopyrite, from Butte, Montana. Specimen is in the University of Wisconsin–River Falls collection, obtained from Ward’s Natural Science Establishment in the 1960s. (Photo by W. Cordua.)

Formula: Cu9S5 Hexagonal


Digenite is a black metallic mineral often found with and mistaken for chalcocite. Both minerals occur in moderate to low temperatures hydrothermal deposits and in supergene enrichment zones.

FOREST COUNTY: Digenite occurs sparingly in the supergene zone of the Crandon deposit near Little Sand Lake. It is found as small grains associated with chalcopyrite, chalcocite, bornite and covellite. (Lambe and Rowe, 1989).

GRANT COUNTY: Heyl et al. (1970 and1978) determined that samples identified originally as chalcocite from the copper deposits in the county are actually digenite. Chalcopyrite and enargite are associated minerals.

RUSK COUNTY: Digenite occurred with chalcocite in the Flambeau Mine, near Ladysmith. (Casey Jones, personal communication)