Crandallite Group

White nodular crandallite with green variscite and other phosphate minerals. From Clay Canyon, near Fairfield, Utah County, Utah. (Photo by W. Cordua.)

Formula: CaAl3(PO4)2(OH)5.H2O Hexagonal


Crandallite is used here to refer to a group of minerals in the Crandallite group, including florencite. Crandallite itself is formed by groundwater precipitation in sedimentary rocks and soils as a result of the breakdown of other phosphate minerals. It can be found with other secondary phosphates such as wardite, variscite and wavellite.

JACKSON COUNTY: Tiny triangular crystals of crandallite occur with wavellite in veins and nodules in the Eau Claire sandstone in road cuts along East Snow Creek Road, about 4 miles north of Black River Falls (Falster, 1986).

RUSK COUNTY: Crandallite-florencite occurs as a tiny euhedral xls. in a meta-saprolite horizon separating the Barron quartzite from the underlying meta-tonalite. This is exposed on the south bank of Weigor Creek, NW SW sec. 9, T36N R7W. (Medaris, 2000).
— Crandallite is reported at the Flambeau Mine, near Ladysmith. (Jones, Jones and LaBerge, 1999)