G = 3·473. H = 5¹⁄₂-6. Brown; opaque. Julianehaab, Greenland. ~Eucolyte.~ R´₄R´´₃Zr(SiO₃)₇, where R´ = K, Na, H, and R´´ = Ce(OH), Fe, Mn, Ca, and Zr(OCl) may replace SiO₂? A very complex mineral. ZrO₂ = 10·9-20; Cer = 0-5·2%. Rhombohedral. G = 3·0-3·1. H = 5-5¹⁄₂. Red to brown; translucent. Double Refraction strong, -ve. Various localities in Norway. _Eucrasite._ An altered Thorite (_q.v._) containing E, Ca, Fe, Mn, Na, Ti, H₂O, etc. Cer = 14; Yttr = 5·9; ThO₂ = 36·0; ZrO₂ = 0·6%. Rhombic (Paijkull). Amorphous, isotropic (Brögger). G = 4·39. H = 4¹⁄₂-5. Brownish black; opaque. Near Brevig, Norway. ~Eudialite.~ A variety of Eucolyte (_q.v._) of the same composition. As Eucolyte. G = 2·92. Double Refraction strong, +ve. Otherwise as Eucolyte. Greenland; Lapland; Arkansas, U.S.A. ~Euxenite.~ E(CbO₃)₃,E₂(TiO₃)₃,1¹⁄₂H₂O; with U and Zr. Cer = 2·3-8·4; Yttr = 13·2-34·6; TiO₂ = 20-23%. ThO₂ + ZrO₂ usually in traces. Orthorhombic; usually massive. G = 4·6-5·0. H = 6¹⁄₂. Brownish-black; translucent to opaque. Hitterö, Brevig, Jolster, Arendal, Norway; Cooglegong, Australia; N. Carolina. ~Fergusonite.~ Approximately E₂O₃, (Cb,Ta)₂O₅, with U, Fe, Ca. Cer = 0·5-13·9; Yttr = 27·9-47·1; ThO₂ + ZrO₂ = 0-7%. [Berzelius found Cer = 36·3; Yttr = 0% in one specimen.] Tetragonal, polar. G = 5·84-4·3 when largely hydrated. H = 5·6. Brown to black. Norway; Australia; Texas, etc. _Florencite._ A silico-phosphate of E and Al. Cer = 28% approximately. G = 3·6. H = 5. Yellow to red. Resinous lustre. Minas Geraes and diamond localities in Brazil. _Fluocerite._ Basic fluoride of rare earth metals, E₂O₃,4EF₃. Cer = 81·4-82·6; Yttr = 1·1-4·3%. Massive. Original hexagonal mineral of Berzelius and Haidinger, probably Tysonite (_q.v._). G = 5·7-5·9. H = 4. Reddish yellow; opaque. Österby, Sweden. _Freyalite._ Silicate of E and Th, with Al, Fe, Mn, Na, aq., etc. Cer = 31·3; ThO₂ = 28·4; ZrO₂ = 6·3%. Amorphous. G = 4·06-4·17. H = 6. Brown; opaque; lustre resinous. Brevig, Norway. ~Gadolinite.~ 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. Geikielite. (Mg,Fe´´)TiO₃. TiO₂ = 56·1-64·8%. Specimens rich in iron are called Picroilmenite. Massive. G = 4 about. H = 6. Purplish or brownish black. Ceylon. Gorceixite. An alumino-phosphate of alkaline and ceria earths. Cer = 0-3%. Microcrystalline. G = 3. H = 6. White to brown. Translucent. Diamond sands of Brazil. Guarinite. Formerly supposed to be dimorphous with Titanite (_q.v._); shown by Zambonini and Prior (1909) to be identical with Hiortdahlite (_q.v._). Hainite.