Andersonite

Andersonite, Na₂Ca(UO₂)(CO₃)₃·6H₂O, or hydrated sodium calcium uranyl carbonate is a rare uranium carbonate mineral that was first described in 1948. Named after Charles Alfred Anderson (1902–1990) of the United States Geological Survey, who first described the mineral species, it is found in sandstone-hosted uranium deposits. It has a high vitreous to pearly luster and is fluorescent. Andersonite specimens will usually glow a bright lemon yellow (or green with blue hints depending on the deposit) in ultraviolet light. It is commonly found as translucent small rhombohedral crystals that have angles close to 90 degrees although its crystal system is nominally trigonal. Its Mohs hardness is 2.5, with an average specific gravity of 2.8.