Читать книгу The Rare Earths: Their Occurrence, Chemistry, and Technology - Stanley Isaac Levy - Страница 131

Mixed ThO₂ + UO₂, with E, Pb, Zr, Si, Fe, etc. ThO₂ = 72-79; Cer = 1-8%.

Rhombohedral; pseudocubic.

G = 8·0-9·7. H = 7. Jet black; bright resinous lustre.

Gem-gravels of Ceylon.