Manganite

Radiating manganite on matrix. From Montreal Mine in Iron County, Wisconsin. (Photo by W. Cordua.)

Formula: MnO(OH) Monoclinic

Description:

Manganite is a lustrous black to steel gray mineral formed in hydrothermal veins or as a groundwater precipitate.

IRON COUNTY: Manganite was found as lustrous striated tabular crystals in clusters lining vugs up to 1 foot across in the iron formation at the Montreal Mine, NE NE sec. 33 T.46N. R.2E. The manganite also occurred as radial fibrous to asbestiform crystals in the vugs (Dickey, 1938).