WGNHS
Wisconsin Geological and Natural History Survey

Lepidolite

Lepidolite (purple) with elbaite in pegmatite, near Fern, Florence County, Wisconsin. Specimen is about 15 cm across. (Photo by W. Cordua.)

Formula: K(Li,Al)2(Si,Al)4O10(F,OH)2 Monoclinic

Description:

Lepidolite is a relative of muscovite, forming pink, purple or yellow flakes or scaly crystals in lithium-rich granite pegmatites.

Lepidolite (pink) showing “line-rock texture” from near Fern, Florence County, Wisconsin. (Photo by Al Falster.)

FLORENCE COUNTY: Lepidolite is abundant as pink to yellow scaly masses with grains averaging 1.0 mm across in the zoned pegmatites in the S 1/2 NW NE sec. 22 T.39N. R.17E, near Fern. Flakes may rarely be up to 1.2 cm in diameter. The lepidolite is associated with elbaite, albite (variety clevelandite), columbite-tantalite, spodumene and other rare minerals (Koehler, 1988, 1989).