WGNHS
Wisconsin Geological and Natural History Survey

Prosopite

Clear prosopite crystal with dark blue azurite. Field of view is about 1 mm. From the Carlota Mine, Top of the World, Gila County, Arizona. (Photo courtesy Brent Thorne; unauthorized reproduction is prohibited.)

Formula: CaAl2(F,OH)8 Monoclinic

Description:

Prosopite is a very rare mineral found in fluorine-enriched pegmatites, greisens and carbonatite.

MARATHON COUNTY: Prosopite was found as tiny grains (300 microns) with cassiterite, topaz and quartz in a greisen zone in the Magurie Pit, part of the LaDick East quarry complex east of Wausau (Buchholz et al., 2005a).