This Specimen has been sold.
1.3" Indigo-Blue Covellite Formation - Butte, Montana
This is a 1.3" wide formation of indigo-blue covellite that was collected from the Leonard Mine in the Butte Mining District of Butte, Montana. There is a small spot of red coloration along one side of this specimen.
Covellite is a copper sulfide mineral with the basic chemical formula CuS. Well formed crystals of covellite are considered rare, with most examples found in massive forms. It typically exhibits an iridescent effect with a lustrous indigo-blue color and occasional spots of red. Covellite is known to commonly form as a secondary mineral in copper sulfide deposits, with Butte, Montana and Tuscany, Italy being two locations that have produced exceptional covellite crystal specimens.