Читать книгу The Rare Earths: Their Occurrence, Chemistry, and Technology - Stanley Isaac Levy - Страница 37

H₄(Na₂,Ca)ZrSi₃O₁₁. ZrO₂ = 29·6-40% (usually 30-33%).

Monoclinic, pseudohexagonal. Becomes truly hexagonal at 140°C.

G = 2·8. H = 6. Yellow to brown; transparent to opaque.

A blue variety is known which contains no calcium.

Islands of Langesund Fiord, Norway; Narsarsuk, Greenland.