The Rare Earths: Their Occurrence, Chemistry, and Technology

by Stanley Isaac Levy

Rhombohedral; habit tabular.

G = 4·13. H = 5-6. Deep brown to black. Transparent.

Langesund Fiord, Norway.

Microlite.

Complex columbate of Ca, E, Fe, etc., with F and H₂O. E₂O₃→ 8%.

Cubic; habit octahedral.

G = 5·48-5·56. H = 5-5¹⁄₂. Red to yellow.

Stockholm, Sweden; Island of Elba; and in U.S.A.

Molengraafite.

Titano-silicate of Ca, Na, Fe, Al, Mn, etc. TiO₂ = 28%.