Formula: Pb5(PO4)3Cl Hexagonal
Description: Pyromorphite is a rare mineral formed by the alteration of primary lead minerals in an oxidized zone or supergene zone environment.
IOWA COUNTY: Heyl et al. (1959) report pyromorphite as a rare secondary mineral in the Upper Mississippi Valley zinc-lead district in southwestern Wisconsin. A specific occurrence mentioned is the Eberle Mine, 5 miles north of Cobb (NW NW sec. 2 T.6N. R.1E.). Here it occurs as “pale green, yellow or brown hexagonal barrel-shaped crystals” associated with pyrite, chalcopyrite, aurichalcite, smithsonite, azurite, malachite and tenorite.