Margaritasite is a yellow, caesium-bearing mineral in the carnotite group. Its chemical formula is (Cs, K, H3O)2(UO2)2V2O8·H2O and its crystal system is monoclinic (space group P21/a). Name and discovery It was first described in 1982 from the Margaritas uranium deposit in the Peña Blanca district of the municipality of Aldama, in the Mexican state of Chihuahua. See also List of minerals References Vanadate minerals Caesium minerals Potassium minerals Uranium(VI) minerals Monoclinic minerals Minerals in space group 14 Minerals described in 1982