Approximately E₂O₃, (Cb,Ta)₂O₅, with U, Fe, Ca. Cer = 0·5-13·9; Yttr = 27·9-47·1; ThO₂ + ZrO₂ = 0-7%. [Berzelius found Cer = 36·3; Yttr = 0% in one specimen.]
Tetragonal, polar.
G = 5·84-4·3 when largely hydrated. H = 5·6. Brown to black.
Norway; Australia; Texas, etc.
Florencite.
A silico-phosphate of E and Al. Cer = 28% approximately.
G = 3·6. H = 5. Yellow to red. Resinous lustre.
Minas Geraes and diamond localities in Brazil.
Fluocerite.
Basic fluoride of rare earth metals, E₂O₃,4EF₃. Cer = 81·4-82·6; Yttr = 1·1-4·3%.