Читать книгу The Rare Earths: Their Occurrence, Chemistry, and Technology - Stanley Isaac Levy - Страница 61

FeO, 2BeO, Y₂O₃, 2SiO₂, where Y = yttrium metals. Cer = 3·4-51·5 (usual 6-20); Yttr = 5-60 (usual 35-48)%.

Monoclinic; habit prismatic. Often amorphous and isotropic.

G = 4·0-4·5. H = 6¹⁄₂-7. Brown and green. Double Refraction strong, +ve.

Ytterby and Fahlun, Sweden; Hitterö and Malö, Norway; Llano Co., Texas; Colorado, etc.