The Rare Earths: Their Occurrence, Chemistry, and Technology

by Stanley Isaac Levy

Orthorhombic; axial ratios unknown.

G = 4·80. H = 5¹⁄₂-6. Black; lustrous.

Burnet Co. Texas.

Yttrofluorite.

nCaF₂ + mYF₃ in isomorphous mixture? Yttr = 20-25; Cer = 1-2%.

Cubic.

G = 3·54-3·56. H = 4¹⁄₂. Closely resembles fluorspar, except in badness of cleavage.

Northern Norway.

Yttrogarnet.

A variety of garnet with E and Zr. Yttr = 1-6·7; ZrO₂ = 0-3%.