The Rare Earths: Their Occurrence, Chemistry, and Technology

by Stanley Isaac Levy

Rhombohedral; isomorphous with Ilmenite, Geikielite, etc.

G = 5·3 (to 4·2 when weathered). H = 6¹⁄₂. Black.

Diamantina, Minas Geraes, Brazil.

Sipylite.

Columbate of E, Zr, Fe, U, Sn, etc.; near [Fergusonite] (q.v.).

Cubic, in octahedra. Usually granular.

G = 4·89. H = 6. Brownish-black; translucent.

Amhurst Co., Virginia.

Steenstrupine.

A silicate of E, Fe, Na, Th, Mn, Al, Ti, H₂O, etc.; near Melanocerite. Cer = 14·4-32·5; Yttr = 0-15·9; ThO₂ = 2·1-7·1%.