East Colusa Mine, Butte, Butte District, Silver Bow Co., Montana, USA
Miniature, 4.0 x 3.7 x 2.0 cm
Well-developed crystals of colusite are rare to uncommon, at best, from the famous mines at Butte, for which the East Colusa Mine is the Type Locality. This excellent specimen features large for the species, reasonably well-developed, bronze-colored colusite crystals to 1.7 cm richly scattered in massive colusite ore. Colusite is a rare copper, vanadium sulfosalt and this piece was collected before 1966.