Ca(UO₂)₂(PO₄)₂.6H₂O

This sample of meta-autunite is displayed in the Smithsonian Museum of Natural History. Meta-autunite is a phosphate mineral of uranium with the composition Ca(UO₂)₂(PO₄)₂.6H₂O. The sample at left is about 12 cm across and is from Central Massif, France.

This sample of meta-autunite is about 20 cm across and is from Daybreak mine, Spokane, Washington.