WGNHS
Wisconsin Geological and Natural History Survey

Cookeite

Pale aggregate of small yellow flakes of cookeite with muscovite, quartz and alkali feldspar. Strickland Quarry, Portland, Connecticut. Scale is in centimeters. (Photo by W. Cordua.)

Formula: LiAl4(AlSi3010)(OH)8 Monoclinic

Description:

Cookeite is a rare alteration product of other lithium minerals found in complex granitic pegmatites.

MARATHON COUNTY: White micaceous material found in a pocket in a pegmatites in the Wausau pluton, has been tentatively identified as cookeite by Falster (1987).