Читать книгу The Rare Earths: Their Occurrence, Chemistry, and Technology - Stanley Isaac Levy - Страница 137

A fluo-borosilicate of E, Th, Ca, with Zr, Na, H₂O, etc. Cer = 44·2-59·2; Yttr = 0·4-4·6; ThO₂ + ZrO₂ = 0-10·6%.

Rhombohedral; in crystals resembling regular tetrahedra.

G = 4·15-4·25. H = 5¹⁄₂. Dark brown; transparent to opaque.

Langesund Fiord, Norway.