[systematic-mineralogy.com] [forum.amiminerals.it] Ba2(Na,Fe,Ca)3MgTi2(Si2O7)2O2F2 http://www.mindat.org/forum.php?read,14,233953,233953#msg-233953 Thu, 23 May 2013 06:26:47 +0000 Phorum 5.2.15a http://www.mindat.org/forum.php?read,14,233953,251895#msg-251895 http://www.mindat.org/forum.php?read,14,233953,251895#msg-251895 www.ingentaconnect.com/content/schweiz/ejm/pre-prints/ejm2174

Lileyite, Ba2(Na,Fe,Ca)3MgTi2(Si2O7)2O2F2, a new lamprophyllite-group mineral from the Eifel volcanic area, Germany
NIKITA V. CHUKANOV, IGOR V. PEKOV, RAMIZA K. RASTSVETAEVA, SERGEY M. AKSENOV, ALEKSANDR E. ZADOV, KONSTANTIN V. VAN, GÜNTER BLASS, WILLI SCHÜLLER and BERND ERNES

The new Mg- and F-dominant lamprophyllite-group mineral lileyite (IMA 2011-021) was found at the Löhley quarry, Üdersdorf, near Daun, Eifel Mountains, Rhineland-Palatinate (Rheinland-Pfalz), Germany, and named for the old name of the type locality, Liley. Associated minerals are nepheline, leucite, augite, magnetite, fluorapatite, perovskite, götzenite. Lileyite is brown, translucent; streak is white. It forms platy crystals up to 0.1 × 0.3 × 0.5 mm in size and their clusters up to 1 mm across on the walls of cavities in an alkaline basalt. Lileyite is brittle, with Mohs hardness of 3–4 and perfect cleavage on (001). Dcalc is 3.776 g/cm3. The new mineral is biaxial (+), α = 1.718(5), β = 1.735(5), γ = 1.755(5), 2V (meas.) = 75(15)°, 2V (calc.) = 86°. The IR spectrum is given. The chemical composition is (EDS-mode electron microprobe, mean of 5 analyses, wt%): SiO2 28.05, BaO 26.39, TiO2 18.53, Na2O 6.75, MgO 4.58, FeO 4.48, CaO 2.30, SrO 2.23, MnO 1.44, K2O 1.41, Nb2O5 0.95, F 3.88, -O=F2 -1.63; total 99.36. The empirical formula based on 18 anions is: Ba1.50Sr0.19K0.26Na1.89Ca0.36Mn0.18Mg0.99Fe0.54Ti2.01Nb0.06Si4.06O16.23F1.77. The simplified formula is: Ba2(Na,Fe,Ca)3MgTi2(Si2O7)2O2F2. The crystal structure was solved using single-crystal X-ray diffraction data (R = 0.024). Lileyite is monoclinic, space group C2/m, a = 19.905(1), b = 7.098(1), c = 5.405(1) Å, β = 96.349(5)°,V = 758.93(6) Å3, Z = 2. The strongest lines of the powder diffraction pattern [d, Å (I, %) (hkl)] are: 3.749 (45) (31–1), 3.464 (76) (510, 311, 401), 3.045 (37) (51–1), 2.792 (100) (221, 511), 2.672 (54) (002, 601, 20-2), 2.624 (43) (710, 42–1). Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4106/1.]]> Uwe Kolitsch IMA Status Fri, 10 Feb 2012 18:04:55 +0000 http://www.mindat.org/forum.php?read,14,233953,233953#msg-233953 http://www.mindat.org/forum.php?read,14,233953,233953#msg-233953 systematic-mineralogy.com]
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Ba2(Na,Fe,Ca)3MgTi2(Si2O7)2O2F2]]> Uwe Kolitsch IMA Status Sun, 28 Aug 2011 16:59:57 +0000