Glaucodot

Glaucodot with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 546. Courtesy of the U.S. Geological Survey Denver Library Photographic Collection. (Photo by Andrew Silver.)

Formula: (Co0.5Fe0.5)AsS Orthorhombic

Description:

Rare gray metallic copper, iron and arsenic sulfide found in hydrothermal deposits.

RUSK COUNTY: Occurs either as pseudo-isometric crystals or as coatings on or pseudomorphs after pyrite, from the Flambeau Copper Mine, Ladysmith. ( Dan Behnke, personal communication)