The Rare Earths: Their Occurrence, Chemistry, and Technology

by Stanley Isaac Levy

Aenigmatite.

A Titanosilicate of Fe´´ and Na, with small proportions of Fe´´´ and Al´´´. Closely allied to the amphiboles. TiO₂ = 7-8%.

Anorthic. Habit prismatic.

G = 3·80-3·86. H = 5¹⁄₂. Black; pleochroism strong.

Greenland and S. Norway.

Aeschynite

A Titanocolumbate of Cerium metals, with Th, Fe, Ca, Mn, aq. Cer = 19·4-24·1; Yttr = 1·1-3·1; ThO₂ = 15·7-17·6; TiO₂ = 21-22%.

Rhombic, holosymmetric. Habit prismatic or tabular.

G = 4·9-5·7. H = 5·6. Black; opaque.

Hitterö, Norway; Miask, Urals; also in Germany and Brazil.