WGNHS
Wisconsin Geological and Natural History Survey

Tenorite

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Black dendrites and masses of tenorite with green malachite on quartz. Arizona. Field of view is about 5 cm. left to right. (Photo by W. Cordua.)

Formula: CuO Monoclinic

Description:Tenorite is a black massive mineral found in the oxidized portions of copper deposits where it is associated with other secondary minerals such as cuprite, malachite, azurite, goethite and hematite. It usually forms as a result of the weathering of copper sulfides such as chalcopyrite.CRAWFORD COUNTY: Tenorite occurs with chalcocite and chalcopyrite at the old Plum Creek copper mine near Wauzeka (SE SW sec. 26 T.8N. R.5W.) (Heyl et. al., 1959).IOWA COUNTY: Tenorite is found in rims around chalcopyrite in mines near Mineral Point, especially in sections 4 and 5 T.4N. R.3E. and in sec. 32 T.5N. R.3E. (Raasch, 1924). Heyl et. al. (1959) report specific occurrences at the Beach Copper Mine (S 1/2 sec. 4 T.4N. R.3E.) and the Wasley Copper Mine (NW sec. 5 T.4N. R.3E.). At these mines tenorite occurs with malachite, azurite, chalcocite, limonite and smithsonite.
– Massive tenorite is found with cuprite, smithsonite, malachite and azurite at the Eberle Mine, NW NW sec. 2 T.6N. R.1E. southeast of Highland. (Heyl, et. al., 1959).

LAFAYETTE COUNTY: Tenorite occurs as a secondary mineral with malachite, azurite, cuprite, copper, chalcocite, pyrolusite and romanechite near Gratiot in the SE NW sec. 36 T.2N. R.3E. The tenorite forms here by alteration of chalcopyrite and bornite.(Heyl, et. al., 1959).
– Tenorite occurs as a secondary mineral with malachite, azurite, cuprite, copper, chalcocite, pyrolusite and romanechite in the SE SW sec. 8 T.1N. R.5E. The tenorite forms here by alteration of chalcopyrite and bornite. (Heyl, et. al., 1959).

RUSK COUNTY: Tenorite forms earthy botryoidal coatings, specks and masses in the gossan zone of the Flambeau Mine massive sulfide deposit, south of Ladysmith (May, 1977).