Autunite
Daybreak Mine
Spokane, Washington

This specimen measures 5cm x 8cm




Autunite      Ca(UO2)2(PO4)2.10-12H2O

Phosphate; hydrous phosphate of calcium and uranium, often with some barium and magnesium

Color and Luster: Lemon- to sulfur yellow, yellowish-green, green; pearly, subadamantine; streak yellowish

Hardness: 2-2.5

Cleavage: Perfect in one direction

Fracture: Flakes yellow

Crystals: Tetragonal; usually thin tabular, also foliated, scaly micaceous aggregates

Photo by Mary Sutherland


Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals