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H₂O, 4R´´O, 3R´´´₂O₃, 6SiO₂, where R´´ = Ca, Fe´´, Be, and R´´´ = Al, Fe´´´, E. An epidote containing rare earths. Cer = 3·6-51 (usually 10-25); Yttr = 0-8 (usually < 3); ThO₂ = 0-3·5%.

Monoclinic; isomorphous with epidote.

G = 3·5-4·2. H = 5¹⁄₂-6. Brown to black; opaque.

Widely distributed in Greenland and Scandinavia.