Cerite is a complex silicate mineral group containing cerium, formula (Ce,La,Ca) 9 (Mg,Fe 3+)(Si O 4) 6 (SiO 3 OH)(OH) 3. [3] The cerium and lanthanum content varies with the Ce rich species (cerite-(Ce)) and the La rich species (cerite-(La)). [5] [6] Analysis of a sample from the Mountain Pass carbonatite gave 35.05% Ce 2 O 3 and 30.04% La 2 O ...