The Rare Earths: Their Occurrence, Chemistry, and Technology

by Stanley Isaac Levy

Monoclinic; habit prismatic.

G = 3·51-3·55. H = 6. Brown to yellow; translucent.

Langesund Fiord, Norway; the Ardennes, France.

Leucosphenite.

BaO,2Na₂O,2(Ti,Zr)O₂,10SiO₂. TiO₂ = 13·2; ZrO₂ = 3·5%.

Monoclinic; wedge-shaped.

G = 3·05. H = 6¹⁄₂. White; transparent.

Narsarsuk, Greenland.

Lewisite.

3R´´Sb₂O₆,2R´´TiO₃, where R = Ca, Fe´´ and Mn. TiO₂ = 11-12%.