The new mineral stetindite, CeSiO4, a cerium end-member of the zircon group
Schlüter, Jochen; Malcherek, Thomas; Husdal, Tomas; Andersen,
published: Aug 1, 2009
ArtNo. ESP154018602005, Price: 29.00 €
The new mineral stetindite (IMA-CNMNC No. 2008-035) has the ideal chemical formula CeSiO4. It is tetragonal with space group I41/amd. Unit-cell data from single-crystal X-ray studies gave a = 6.9746(7), c = 6.2055(8) (Å), V = 301.87(7) Å3, Z = 4. Stetindite is the Ce4+-dominant analogue of zircon (ZrSiO4) and hafnon (HfSiO4). The strongest reflections in the X-ray powder diffraction data are as follows dobs. (Å) (I, hkl): 3.478 (100, 200), 1.789 (39, 312), 4.616 (30, 101) and 2.617 (30, 112). Stetindite was found in the Stetind pegmatite, Tysfjord, 135 km NE of Bodø, northern Norway. It occurs as pale yellow to colourless crystals mostly as diverging aggregates of acicular crystals which reach a length of 1.5 mm and a thickness of 0.05 mm. The calculated density is 5.03 g/cm3. The mineral is optically uniaxial positive with a calculated main refractive index of 2.01. Stetindite is found in vugs of yttrian fluorite masses and is closely associated with hematite, hundholmenite-(Y), quartz, törnebohmite-(Ce), vyuntspakhkite-(Y), calcioancylite-(Nd), Kozoite-(Nd), Nd-rich bastnäsite and a new Ca-Y-Al-F-silicate. Chemical analyses gave (wt.%): CeO2 65.17, Y2O3 6.35, Gd2O3 1.32, SiO2 25.94, F 0.69, O ≡ F -0.29, sum 99.18 wt.%. The resulting empirical formula based on 4 anions is (Ce0.87,Y0.13,Gd0.02)Si1.00O3.92F0.08.