Abstract
A new mineral, günterblassite, has been found in the basaltic quarry at Mount Rother Kopf near Gerolstein, Rheinland-Pfalz, Germany as a constituent of the late assemblage of nepheline, leucite, augite, phlogopite, åkermanite, magnetite, perovskite, a lamprophyllite-group mineral, götzenite, chabazite-K, chabazite-Ca, phillipsite-K, and calcite. Günterblassite occurs as colorless lamellar crystals up to 0.2 × 1 × 1.5 mm in size and their clusters. The mineral is brittle, with perfect cleavage parallel to (001) and less perfect cleavage parallel to (100) and (010). The Mohs hardness is 4. The calculated and measured density is 2.17 and 2.18(1) g/cm3, respectively. The IR spectrum is given. The new mineral is optically biaxial and positive as follows: α = 1.488(2), β = 1.490(2), γ = 1.493(2), 2V meas = 80(5)°. The chemical composition (electron microprobe, average of seven point analyses, H2O is determined by gas chromatography, wt %) is as follows: 0.40 Na2O, 5.18 K2O, 0.58 MgO, 3.58 CaO, 4.08 BaO, 3.06 FeO, 13.98 Al2O3, 52.94 SiO2, 15.2 H2O, and the total is 98.99. The empirical formula is Na0.15K1.24Ba0.30Ca0.72Mg0.16F 2+0.48 [Si9.91Al3.09O25.25(OH)3.75] · 7.29H2O. The crystal structure has been determined from a single crystal, R = 0.049. Günterblassite is orthorhombic, space group Pnm21; the unit-cell dimensions are a = 6.528(1), b = 6.970(1), c = 37.216(5) Å, V = 1693.3(4) Å3, Z = 2. Günterblassite is a member of a new structural type; its structure is based on three-layer block [Si13O25(OH,O)4]. The strong reflections in the X-ray powder diffraction pattern [d Å (I, %) are as follows: 6.532 (100), 6.263 (67), 3.244 (49), 3.062 (91), 2.996 (66), 2.955 (63), and 2.763 (60). The mineral was named in honor of Günter Blass (born in 1943), a well-known amateur mineralogist and specialist in electron microprobe and X-ray diffraction. The type specimen of günterblassite is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, with the registration number 4107/1.
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Cadoni, M. and Ferraris G., Two New Members of the Rhodesite Mero-Plesiotype Series Close to Delhayelite and Hydrodelhayclite: Synthesis and Crystal Structure, Eur. J. Mineral., 2009, vol. 21, pp. 485–493.
Ferraris, G. and Gula, A., Polysomatic Aspects of Microporous Minerals Heterophyllosilicates, Polysepioles and Rhodesite-Related Structures, Rev. Miner. Geochem., 2005, vol. 57, pp. 69–104.
Hesse, K.-F., Liebau, F., and Merlino, S., Crystal Structure of Rhodesite, HK1 − x Na x + 2y Ca2 − y {1B, 3, 2 2− }[Si8O19](6 − z)H2O, from Three Localities and Its Relation to Other Silicates with Dreier Double Layers, Ztschr. Kristal., 1992, vol. 199, pp. 25–48.
Mineraly. Spravochnik. T. IV. Vyp. 2 (Minerals. Reference Book, Vol. IV. Issue 2) Chukhrov, F.V., Ed., Moscow: Nauka, 1992.
Pekov, I.V., Zubkova, N.V., Chukanov, N.V., et al., Crystal Chemistry of Delhayelite and Hydrodelhayelite, Dokl. Earth. Sci., 2009, vol. 428, no. 7, pp. 1216–1221.
Pekov, I.V., Zubkova, N.V., Chukanov, N.V., et al., Fivegite K4Ca2[AlSi7O17(O2 − x OHx)][(H2O)2 − x OHx]Cl, A New Mineral Species from the Khibiny Alkaline Pluton of the Kola Peninsula in Russia, Geol. Ore Dep., 2011a, vol. 53, spec. issue no. 7 (Zapiski Russian Mineral. Soc.), pp. 591–603.
Pekov, I.V., Zubkova, N.V., Chukanov, N.V., et al., Delhayelite and Mountainite Mineral Families: Crystal Chermical Relationship, Microporous Character and Genetic Features, Minerals As Advanced Materials II, S.V. Krivovichev, Ed., Berlin: Springer, 2011b, pp. 213–219.
Pekov, I.V., Zubkova, N.V., Filinchuk, Ya.E., et al., Shlykovite, KCa[Si4O9(OH)] · 3H2O and cryptophyllite K2Ca[Si4O10] · 5H2O, New Mineral Species from the Khibiny Alkaline Pluton of the Kola Peninsula in Russia, ZRMO, 2010, vol. 139, no. 1, pp. 37–50.
Rastsvetaeva, R.K., Aksenov, S.M., and Chukanov, N.V., Crystal Structure of Günterblassite, a New Mineral with a Triple Tetrahedral Layer. Dokl. Chem., 2012, vol. 442,part 2, pp. 57–62.
Zubkova, N.V., Pekov, I.V., Pushcharovsky, D.Yu., et al., The Crystal Structure and Refined Formula of Mountainite, KNa2Ca2[Si8O19(OH)] · 6H2O, Ztschr. Krist., 2009, vol. 224, pp. 389–396.
Zubkova, N.V., Filinchuk, Ya.E., Pekov, I.V., et al., Crystal Structures of Shlykovite and Cryptophyllite: Comparative Crystal Chemistry of Phyllosilicate Minerals of the Mountainite Family, Eur. J. Mineral., 2010, vol. 22, no. 4, pp. 547–555.
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Original Russian Text © N.V. Chukanov, R.K. Rastsvetaeva, S.M. Aksenov, I.V. Pekov, N.V. Zubkova, S.N. Britvin, D.I. Belakovskiy, W. Schüller, B. Ternes, 2012, published in Zapiski Rossiiskogo Mineralogicheskogo Obshchestva, 2012, No. 1, pp. 71–79.
The new mineral species günterblassite and its name were approved by the Commission on New Minerals, Nomenclature, and Mineral Classification of the International Mineralogical Association on June 2, 2011 (IMA no. 2011-032).
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Chukanov, N.V., Rastsvetaeva, R.K., Aksenov, S.M. et al. Günterblassite, (K,Ca)3 − x Fe[(Si,Al)13O25(OH,O)4] · 7H2O, a new mineral: the first phyllosilicate with triple tetrahedral layer. Geol. Ore Deposits 54, 656–662 (2012). https://doi.org/10.1134/S1075701512080065
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DOI: https://doi.org/10.1134/S1075701512080065