Chalcanthite

Blue coating of chalcanthite on sericite schist. Field of view is about 1 cm across. From the Flambeau Mine in Ladysmith, Rusk County, Wisconsin. (Photo by W. Cordua.)

Formula: CuSO4.5H2O TRICLINIC

Description:

Chalcanthite usually forms as crusts on other copper minerals during weathering. It is a water soluble mineral that does not survive long in Wisconsin’s climate.

RUSK COUNTY: Sky blue coatings of chalcanthite were abundant as post-mining deposits on rock surfaces in the Flambeau Mine, Ladysmith (Cordua, field notes).