Читать книгу The Rare Earths: Their Occurrence, Chemistry, and Technology - Stanley Isaac Levy - Страница 87

Mixture of oxides, chiefly of Th and U; also Fe, Ca, Mg, Pb, Na, B, Ta, etc. Composition very complex. ThO₂ = 45·3; E₂O₃ = 1·9; ZrO₂ = 1%.

Tetragonal, resembling thorite (q.v.).

G = 5·42. H = 5¹⁄₂. Black; opaque.

Bluffton, Llano Co., Texas.