Open AccessIlimaussite, a new rare earth-niobium-barium silicate from Ilímaussaq South Greenland
Author(s) -
Е. И. Семенов,
M.E Kazakova,
V.J Bukin
Publication year - 1968
Publication title -
bulletin
Language(s) - English
Resource type - Journals
eISSN - 2597-2936
pISSN - 0105-3507
DOI - 10.34194/bullggu.v75.6613
Subject(s) - nepheline , geochemistry , mineral , geology , barium , mineralogy , hydrothermal circulation , massif , sodalite , silicate , nepheline syenite , materials science , chemistry , inorganic chemistry , zeolite , metallurgy , biochemistry , organic chemistry , seismology , catalysis
A new mineral - Na4Ba2CeFeNb2Si8O28.5H2O - found in a hydrothermal vein in nepheline-sodalite syenite (naujaite) of the llímaussaq alkaline massif is described. The mineral is named ilimaussite after the locality where it was found. It forms brownish-yellow lamellae and is associated with ussingite, chkalovite and epistolite. The specific gravity is 3.6. The mineral is optically uniaxial positive; ne = 1.695, no = 1.689. The mineral is hexagonal, ao = 10.80, co = 20.31, Vo = 2052 Å3, Z = 3. The chemical composition is: SiO2 - 31.28, TiO2 - 1.64, Nb2O5 - 13.20, TR2O3 - 10.60, Fe2O3 - 3.18, BaO - 23.62, Na2O - 7.00, K2O - 3.80, loss by ignition - 6.43; total 100. 75.