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Fluoroleakeite, NaNa2(Mg2Fe3+ 2Li)Si8O22F2, a new mineral of the amphibole group from the Verkhnee Espe deposit, Akjailyautas Mountains, Eastern Kazakhstan District, Kazakhstan: description and crystal structure

  • F. Cámara (a1), F. C. Hawthorne (a2), N. A. Ball (a2), G. Bekenova (a3), A. V. Stepanov (a3) and P. E. Kotel'nikov (a3)...

Abstract

Fluoroleakeite, NaNa2(Mg2Fe3+ 2Li)Si8O22F2 is a new mineral of the amphibole group from the Verkhnee Espe deposit, Akjailyautas mountains, eastern Kazakhstan district, Kazakhstan. The granites and their host rocks have been intensely reworked by post-magmatic and host-rock fluids, resulting in intense recrystallization, enrichment in F, Li and rare elements, and replacement of primary biotite and sodic-calcic amphiboles by Li-bearing riebeckite, aegirine, astrophyllite and other sodic minerals including fluoroleakeite. Crystals are prismatic parallel to [001] with {100} and {110} faces and cleavage surfaces, and the prism direction is terminated by irregular fractures. Grains are up to 3 mm long, and occur as isolated crystals, as small aggregates, and as inclusions in cámaraite. Crystals are black with a very pale grey to colourless streak. Fluoroleakeite is brittle, has a Mohs hardness of 6 and a splintery fracture; it is non-fluorescent with perfect {110} cleavage, no observable parting, and has a calculated density of 3.245 g cm–3. In plane-polarized light, it is pleochroic, X = pale grey-green, Y = medium grey, Z = grey-brown; X^a = 14.1° (in β obtuse), Yb, Z^c = 75.9° (in β acute). Fluoroleakeite is biaxial negative, α = 1.663(2), β = 1.673(2), γ = 1.680(2); 2Vobs = 80.9(6)°, 2Vcalc = 79.4°

Fluoro-leakeite is monoclinic, space group C2/m, a = 9.8927(3), b = 17.9257(6), c = 5.2969(2) Å, β = 103.990(1)°, V = 905.7(1) Å3, Z = 2. The strongest ten X-ray diffraction lines in the powder pattern are [d in Å(I)(hkl)]: 2.718(100)(151), 8.434(40)(110), 4.464(30)(021), 3.405(30)(131), 3.137(20)(310), 2.541(20)(), 2.166(20)(261), 2.325(15)(), 2.275(15)() and 2.806(10)(330). Analysis by a combination of electron microprobe and crystal-structure refinement gives SiO2 53.34, Al2O3 0.62, TiO2 1.27, V2O3 0.05, Fe2O3 15.10, FeO 6.00, MnO 2.04, ZnO 0.18, MgO 6.40, CaO 0.13, Na2O 9.08, K2O 1.98, Li2O 1.10, F 3.33, H2Ocalc 0.16, sum 99.39 wt.%. The formula unit, calculated on the basis of 23 O, is A (Na0.64K0.38)(Na1.98Ca0.02)(Li0.66Mg1.42Fe0.75 2+Mn0.26 2+Zn0.02Fe1.69 3+V0.01 3+Ti0.14 4+Al0.03) (Si7.93Al0.07)O22(F1.57OH0.16O0.27). Crystal-structure refinement shows Li to be completely ordered at the M(3) site. Fluoroleakeite, ideally NaNa2(Mg2Fe2 3+Li)Si8O22F2, is related to end-member leakeite, NaNa2(Mg2Fe2 3+Li)Si8O22(OH)2 by the substitution F → (OH).

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Armbruster, T., Oberhänsli, R., Bermanec, V. and Dixon, R. (1993) Hennomartinite and kornite: two new Mn3+ rich silicates from the Wessels Mine, Kalahar i, South Africa. Schweizerische Mineralogische und Petrographische Mitteilungen, 73, 349355.
Bartelmehs, K.L., Bloss, F.D., Downs, R.T. and Birch, J.B. (1992) Excalibr II. Zeitschrift für Kristallographie, 199, 185196.
Cámara, F., Sokolova, E. and Nieto, F. (2009) Cámaraite, Ba3NaTi4(Fe2+,Mn)8(Si2O7)4O4 (OH,F)7. II. The crystal structure and crystal chemistry of a new group-II Ti-disilicate mineral. Mineralogical Magazine, 73, 855870.
Guan, Ya.S., Simonov, V.I. and Belov, N.V. (1963) Crystal structure of bafertisite, BaFe2TiO[Si2O7](OH)2 . Doklady Akademii Nauk SSSR, 149, 123126.
Hawthorne, F.C. (1983) The crystal chemistry of the amphiboles. The Canadian Mineralogist, 21, 173480.
Hawthorne, F.C. and Grundy, H.D. (1972) Positional disorder in the A-site of clino-amphiboles. Nature, 235, 72.
Hawthorne, F.C. and Oberti, R. (2007) Amphiboles: crystal chemistry. Pp. 154 in: Amphiboles: Crystal Chemistry, Occurrence and Health Issues (Hawthorne, F.C. and Oberti, R., editors). Reviews in Mineralogy and Geochemistry, 67, Mineralogical Society of America, Washington D. C, and the Geochemical Society, St. Louis, Missouri, USA.
Hawthorne, F.C., Oberti, R., Ungaretti, L. and Grice, J.D. (1992) Leakeite, NaNa2(Mg2Fe2 3+ Li)Si8O22(OH)2, a new amphibole from the Kajlidongri manganese mine, Jhabua district, Madhya Pradesh, India. American Mineralogist, 77, 11121115.
Hawthorne, F.C., Ungaretti, L., Oberti, R., Bottazzi, P. and Czamanske, G.K. (1993) Li an important component in igneous alkali amphiboles. American Mineralogist, 78, 733745.
Hawthorne, F.C., Ungaretti, L., Oberti, R., Cannillo, E. and Smelik, E.A. (1994) The mechanism of [6]Li incorporation in amphiboles. American Mineralogist, 79, 443451.
Hawthorne, F.C., Oberti, R. and Sardone, N. (1996 a) Sodium at the A site in clinoamphiboles: the effects of composition on patterns of order. The Canadian Mineralogist, 34, 577593.
Hawthorne, F.C., Oberti, R., Ungaretti, L., Ottolini, L., Grice, J.D. and Czamanske, G.K. (1996 b) Fluorferro- leakeite, NaNa2(Fe2 2+Fe3 2+Li)Si8O22F2, a new alkaliamphi bole from the Cañada Pinabete pluton, Questa, New Mexico U.S.A. American Mineralogist, 81, 226228.
Hawthorne, F.C., Oberti, R., Zanetti, A. and Czamanske, G.K. (1998) The role of Ti in hydrogen-deficient amphiboles: Sodic-calcic and sodic amphiboles from Coyote Peak, California. The Canadian Mineralogist, 36, 12531265.
Leake, B.E., Woolley, A.R., Arps, C.E.S., Birch, W.D., Gilbert, M.C., Grice, J.D., Hawthorne, F.C., Kato, A., Kisch, H.J., Krivovichev, V.G., Linthout, K., Laird, J., Mandarino, J.A., Maresch, W.V., Nickel, E.H., Rock, N.M.S., Schumacher, J.C., Smith, D.C., Stephenson, N.C.N., Ungaretti, L., Whittaker, E.J.W. and Guo, Y. (1997) Nomenclature of amphiboles: Report of the subcommittee on amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35, 219246.
Leake, B.E., Woolley, A.R., Birch, W.D., Burke, E.A.J., Ferraris, G., Grice, J.D., Hawthorne, F.C., Kisch, H.J., Krivovichev, V.G., Schumacher, J.C., Stephenson, N.C.N. and Whittaker, E.J.W. (2003) Nomenclature of amphiboles: additions and revisions to the International Mineralogical Association's amphibole nomenclature. The Canadian Mineralogist, 41, 13551370.
Matsubara, S., Miyawaki, R., Kurosawa, M. and Suzuki, Y. (2002) Potassicleakeite, a new amphibole from the Tanohata mine, Iwate prefecture, Japan. Journal of Mineralogical and Petrological Sciences, 97, 177184.
Oberti, R., Ungaretti, L., Cannillo, E. and Hawthorne, F.C. (1992) The behaviour of Ti in amphiboles. I. Four- and six-coordinated Ti in richterite. European Journal of Mineralogy, 3, 425439.
Oberti, R., Hawthorne, F.C., Cámara, F. and Raudsepp, M. (1998) Synthetic fluoro-amphiboles: site preferences of Al, Ga, Sc and inductive effects on mean bond-lengths of octahedra. The Canadian Mineralogist, 36, 12451252.
Oberti, R., Hawthorne, F.C., Cannillo, E. and Cámara, F. (2007 a) Long-range order in amphiboles. Pp. 125171 in: Amphiboles: Crystal Chemistry, Occurrence and Health Issues (Hawthorne, F.C. and Oberti, R., editors). Reviews in Mineralogy and Geochemistry, 67, Mineralogical Society of America, Washington D.C., and the Geochemical Society, St. Louis, Missouri, USA.
Oberti, R., Della Ventura, G. and Cámara, F. (2007 a) New amphibole compositions: natural and synthetic. Pp. 89123 in: Amphiboles: Crystal Chemistry, Occurrence and Health Issues (Hawthorne, F.C. and Oberti, R., editors). Reviews in Mineralogy and Geochemistry, 67, Mineralogical Society of America, Washington D.C., and the Geochemical Society, St. Louis, Missouri, USA.
Oberti, R., Cámara, F., Ball, N.A. and Hawthorne, F.C. (2009) Fluoro-aluminoleakeite, Na Na2 (Mg2 Al2 Li) S8 O22 F2, a new mineral of the amphibole group from Norra Karr, Sweden: description and crystal structure. Mineralogical Magazine, 73, 817824.
Pouchou, J.L. and Pichoir, F. (1985) ‘PAP’ φ(ρZ) procedure for improved quantitative microanalysis. Pp. 104160 in: Microbeam Analysis. San Francisco Press, California, USA.
Sheldrick, G.M. (1998) SADABS UserGuide . University of Gö ttingen, Germany.
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112122.
Sokolova, E. (2006) From structure topology to chemical composition. I. Structural hierarchy and stereochemistry in titanium disilicate minerals. The Canadian Mineralogist, 44, 12731330.
Sokolova, E., Abdu, Y., Hawthorne, F.C., Stepanov, A.V., Bekenova, G.K. and Kotel’nikov, P.E. (2009 a) Cámaraite, Ba3Na(Fe2+,Mn)8Ti4(Si2O7)4O4(OH,F)7, a new titanium-silicate mineral from the Verkhnee Espe deposit, Akjailyautas mountains, Kazakhstan. Mineralogical Magazine, 73, 847854.
Sokolova, E., Cámara, F., Hawthorne, F.C. and Abdu, Y. (2009 b) From structure topology to chemical composition. VII. Titanium silicates: the crystal structure and crystal chemistry of jinshajiangite. European Journal of Mineralogy, 21, 871883.
Tait, K.T., Hawthorne, F.C., Grice, J.D., Ottolini, L. and Nayak, V.K. (2005) Dellaventuraite, NaNa2 (MgMn2 3+Ti4+Li)Si8O22O2, a new anhydrous amphibole from the Kajlidongri Manganese Mine, Jhabua District, Madhya Pradesh, India. American Mineralogist, 90, 304309.

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Fluoroleakeite, NaNa2(Mg2Fe3+ 2Li)Si8O22F2, a new mineral of the amphibole group from the Verkhnee Espe deposit, Akjailyautas Mountains, Eastern Kazakhstan District, Kazakhstan: description and crystal structure

  • F. Cámara (a1), F. C. Hawthorne (a2), N. A. Ball (a2), G. Bekenova (a3), A. V. Stepanov (a3) and P. E. Kotel'nikov (a3)...

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