The Rare Earths: Their Occurrence, Chemistry, and Technology

by Stanley Isaac Levy

Monoclinic; habit prismatic.

G = 3·84. H = 6¹⁄₂. Black; translucent to opaque.

Achmatovsk, Urals.

Bastnäsite (Harmatite).

Hydrated fluocarbonate of Cerium metals, E(F)CO₃. Cer = 64-93·5; ThO₂ = 0-10%.

Hexagonal prisms, pseudomorphous after [Tysonite] (q.v.); or massive.

G = 4·9-5·2. H = 4-4¹⁄₂. Yellow to brown; transparent.

Bastnäs, Sweden; Pike’s Peak, Colorado.

Beckelite.

Zirconosilicate of rare earths and lime, Ca₃E₄(Si,Zr)₃O₁₅. Cer = 59·7; Yttr = 2·8; ZrO₂ = 2·5%.