Читать книгу The Rare Earths: Their Occurrence, Chemistry, and Technology - Stanley Isaac Levy - Страница 53

R´₄R´´₃Zr(SiO₃)₇, where R´ = K, Na, H, and R´´ = Ce(OH), Fe, Mn, Ca, and Zr(OCl) may replace SiO₂? A very complex mineral. ZrO₂ = 10·9-20; Cer = 0-5·2%.

Rhombohedral.

G = 3·0-3·1. H = 5-5¹⁄₂. Red to brown; translucent. Double Refraction strong, -ve.

Various localities in Norway.