WGNHS
Wisconsin Geological and Natural History Survey

Silver

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Silver in Flambeau Mine in Rusk County, Wisconsin. Cluster about 0.5 mm across. (Photo and specimen by Dan Behnke.)

Formula: Ag Isometric

Description:Native silver is found in hydrothermal veins or, more rarely, as a supergene mineral. It is associated with gold, and a variety of sulfides such as galena, pyrite and acanthite. Major silver mineralization is found with native copper in nearby Michigan at the White Pine Mine and further north in the Keweenaw Peninsula. Similar deposits are not known from equivalent bedrock in Wisconsin. Native silver is found sporadically in glacial drift with copper transported from the Michigan deposits.ASHLAND COUNTY: Numerous small shows of silver were worked briefly in the 1880’s and 1890’s in several places in the county. These include the Northern Belle mine (SW sec. 22 T.45N R4W) the Jacobs prospect (sec. 32 T45N R2W) and the Holmes prospect (sec. 34 T.45N. R.2W) (Cox, 2002).BAYFIELD COUNTY: A Keweenawan conglomerate body sampled in sec. 11 T.44N. R.6W. north of Namekagon Lake contained from 0.36 to 1.74 troy ounces of silver per ton. (Dutton, 1972). It is not known if the silver is present as native silver or as some other mineral.

DOUGLAS COUNTY: Grant (1901) tentatively identified native silver as a coating on native copper wires found in veins at the Copper Creek locality (SW sec. 14 and SE sec. 15 T.47N. R.14W. now in Pattison State Park.

—One sample containing native silver was found at the Weyerhauser Mine (NW SE sec. 12 T.43N. R.10W). The silver was found in mineralized Keweenawan basalt flows with prehnite, native copper, malachite and azurite (Smith, 1947).

MARINETTE COUNTY: Samples from “porphyroblastic argillite” exposed in an old shaft in NE SW sec. 16 T.36N. R.12E. contained 12.39 ounces of silver and 0.61 ounces of gold per ton. (Dutton and Bradley, 1970). It is not known if the silver is present as native silver or as some other mineral.

ONEIDA COUNTY: Native silver occurs with gold, electrum, silver sulfides and sulfosalts in drill core taken through the Lynne Deposit in the SW corner of the county. (Kennedy et al., 1991).

RUSK COUNTY: Native silver occurred as sheets along joint surfaces with native copper at the Flambeau Copper Mine, south of Ladysmith. It was also found as tiny clusters and rosettes of crystals in dolomite at this mine.