Uranophane Ca(UO2)2(SiO3OH)25H2O is a rare calcium uranium silicate hydrate mineral that forms from the oxidation of uranium bearing minerals. Uranophane is also known as uranotile. It has a yellow color and is radioactive.

Care should be taken when handling it as it flakes easily and could become embedded in the skin. Since the material is radioactive, these flakes would constantly bombard the body with ionizing radiation.