Cerite is a complex silicate mineral group containing cerium, formula (Ce,La,Ca)9(Mg,Fe3+)(SiO4)6(SiO3OH)(OH)3. The cerium and lanthanum content varies with the Ce rich species and the La rich species. Analysis of a sample from the Mountain Pass carbonatite gave 35.05% Ce2O3 and 30.04% La2O3.