WGNHS
Wisconsin Geological and Natural History Survey

Aurichalcite

Aurichalcite with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 080. Courtesy of the U.S. Geological Survey Denver Library Photographic Collection. (Photo by Andrew Silver.)

Formula: (Zn,Cu)5(CO3)2(OH)6 Monoclinic

Description:

Aurichalcite with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 082. Courtesy of the U.S. Geological Survey Denver Library Photographic Collection. (Photo by Andrew Silver.)

Aurichalcite forms bluish green radical fibrous crystals in zones where zinc and copper minerals are subjected to oxidization and redeposition of the metals in the present of carbon dioxide.

IOWA COUNTY: Reportedly found as “pale blue silky tuffs” at the Eberle mine, 5 miles north of Cobb in the NW 1/4 NW 1/4 Sec. 2 T.^N. R.1E. It is here associated with malachite, azurite, cuprite, chalcocite, sphalerite and smithsonite (Heyl, et. al., 1959; Wisc. Geol. and Nat. Hist. Surv. files).
— Found at the Steppler Farm, 4 miles southwest of Highland on County Trunk I in the SE 1/4 SE 1/4 Sec. 7 T.6N. R.1E. Associated minerals are chalcopyrite, chalcocite, azurite, malachite, chrysocolla, sphalerite and smithsonite (WGNHS files) (Heyl et al., 1959).

LAFAYETTE COUNTY: Found as tiny bluish green radiating crystals associated with calcite, chalcopyrite and sphalerite on old mine dumps on the SE edge of the SE 1/4 Sec. 12 T.1N. R.2E (Heyl et al., 1959).