WGNHS
Wisconsin Geological and Natural History Survey

Glaucodot

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Cluster of dark gray glaucodot
Glaucodot with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 546. (Image courtesy U.S. Geological Survey Denver Library Photographic Collection; image 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)