Autunite crystals, a selection of specimens of this crystallized mineral species. Autunite is a mineral with many collector’s items presented here with a description, one or more photos and sometimes a video. These autunites are for sale. It is a hydrated phosphate of uranium and calcium, with the chemical formula Ca(UO2)2(PO4)2 – 10-12 H2O, quadratic crystal system. It’s a radioactive mineral.