Skip to main content Accessibility help

Odigitriaite, CsNa5Ca5[Si14B2O38]F2, a new caesium borosilicate mineral from the Darai-Pioz alkaline massif, Tajikistan: Description and crystal structure

  • Atali A. Agakhanov (a1) (a2), Leonid A. Pautov (a2), Elena Sokolova (a3), Frank C. Hawthorne (a3), Vladimir Yu Karpenko (a1), Oleg I. Siidra (a1) and Vyacheslav A. Muftakhov (a1) (a4)...


Odigitriaite, a new Cs, Na, Ca borosilicate mineral, was discovered in moraine adjacent to the Darai-Pioz alkaline massif in the upper reaches of the Darai-Pioz river at the intersection of the Turkestansky, Zeravshansky and Alaisky mountain ridges, Tajikistan. It occurs as irregular thin flakes associated with quartz, pectolite, baratovite, fluorite, pekovite, polylithionite, aegirine, leucosphenite, pyrochlore, neptunite, reedmergnerite, mendeleevite-(Ce), zeravshanite and sokolovaite. It is colourless with a white streak, is translucent and has a vitreous lustre; it does not fluoresce under ultraviolet light. Odigitriaite is brittle with an uneven fracture and a Mohs hardness of 5. The calculated density is 2.80(2) g/cm3. The indices of refraction are α = 1.502, β = 1.564, γ = 1.576; 2Vobs = 46(2)°, dispersion is weak r > v, and there is no pleochroism. The chemical composition is as follows (electron microprobe, H2O calculated from structure): SiO2 55.30, Al2O3 0.09, Y2O3 0.44, MnO 0.94, FeO 0.10, PbO 0.21, K2O 0.01 Cs2O 8.36, B2O3 4.75, H2O 0.37, F 1.74, O = F2 –0.74, total 99.43 wt.%. The empirical formula of odigitriaite is Cs0.90Na5.12Ca4.68Mn0.20Y0.06Fe0.02Pb0.01[Si13.92Al0.03B2.06O38]F1.39(OH)0.62. The end-member formula is CsNa5Ca5[Si14B2O38]F2. The strong reflections in the powder X-ray diffraction pattern are: [(d, Å), (I, %), (hkl)]: 5.45 (25) (1 1 3), 4.66 (33) (3 1 1), 4.40 (26) (0 2 2), 4.10 (36) (3 1 3), 3.95 (25) (3̄ 1 3), 2.85 (31) (2 2 2), 2.68 (40) (0 0 6), 3.62 (45) (0 2 4), 3.35 (100) (2̄ 2 4), 3.31 (30) (3̄ 1 5), 3.25 (35) (4 0 4), 3.04 (60) (4̄ 2 2), 2.925 (22) (4̄ 2 3), 1.813 (23) (9 1 0). Odigitriaite is monoclinic, space group C2/c, a = 16.652(5), b = 9.598 (3), c = 22.120(7) Å, β= 92.875(14)°, V = 3530.9(1.9) Å3, Z = 4. The crystal structure of odigitriaite was solved by direct methods and refined to an R 1 value of 2.75% based on single-crystal X-ray data. It is a double-layer sheet-borosilicate mineral; Cs and Na are intercalated within the double-layer sheet, and the double layers are linked by interstitial Ca and Na atoms.


Corresponding author


Hide All
Agakhanov, A.A., Pautov, L.A., Belakovskiy, D.I., Sokolova, E.V. and Hawthorne, F.C. (2003) Telyushenkoite CsNa6[Be2﹛Si,A1,Zn)18O39F2] - a new cesium mineral of the leifite group. New Data on Minerals, 38, 58.
Agakhanov, A.A., Pautov, L.A., Uvarova, Y.A., Sokolova, E.V., Hawthorne, F.C. and Karpenko, YY (2005) Senkevichite, CsKNaCa2TiO[Si7O18(OH)], a new mineral. New Data on Minerals, 40, 1722.
Agakhanov, A.A., Pautov, L.A., Karpenko, YYu, Sokolova, E. and Hawthorne, F.C. (2012) Kirchhoffite, CsBSi2O6, a new mineral species from the Darai-Pioz Alkaline Massif, Tajikistan: Description and crystal structure. The Canadian Mineralogist, 50, 523529.
Agakhanov, A.A., Pautov, L.A., Sokolova, E., Hawthorne, F.C., Karpenko, YYu, Siidra, O.I. and Garanin, V.K. (2015) Mendeleevite-(Nd), IMA 2015-031. Mineralogical Magazine, 79, 941947.
Dusmatov, V.D. (1968) On mineralogy of one alkaline massif. Pp. 134135 in: Alkaline Rocks of Kirgizia and Kazakhstan, Ilym, Frunze [in Russian]. alkaline massif (Southern Tien-Shan). PhD dissertation, Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements, Moscow, 171 pp. [in Russian].
Hawthorne, F.C. (2015) Generating functions for stoichi-ometry and structure of single- and double-layer sheet-silicates. Mineralogical Magazine, 79, 16751709.
Hawthorne, F.C., Ungaretti, L. and Oberti, R. (1995) Site populations in minerals: terminology and presentation of results of crystal-structure refinement. The Canadian Mineralogist, 33, 907911.
Liebau, F. (1985) Structural Chemistry of Silicates. Springer-Verlag, Berlin.
Pautov, L.A., Agakhanov, A.A., Uvarova, Y.A., Sokolova, E.V. and Hawthorne, F.C. (2004) Zeravshanite, Cs4Na2Zr3(Si18O45)(H2O)2, a new cesium mineral from Dara-i-Pioz massif (Tajikistan). New Data on Minerals, 39, 2025.
Pautov, L.A., Agakhanov, A. A and Bekenova, G.K. (2006) SokolovaiteCsLi2AlSi4O10F2: a new mineral species of the mica group. New Data on Minerals, 41, 513.
Pautov, L.A., Agakhanov, A.A., Karpenko, YYu, Sokolova, E. and Hawthorne, F.C. (2013) Mendeleevite-(Ce), (Cs,n)6(OCs)6(QK)6(REE,Ca,n)3o(Si7o0175)(H20, ‘OH,F,Q)35: a new mineral from the Darai-Pioz massif, Tajikistan. Doklady Earth Sciences, 452, 10231026.
Pouchou, J.L. and Pichoir, F. (1985) “PAP” procedure for improved quantitative microanalysis. Pp. 104-106 in: Microbeam Analysis (J.T Armstrong, editor). San Francisco Press, San Francisco, California, USA.
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112122.
Sokolova, E., Huminicki, D.M.C., Hawthorne, F.C., Agakhanov, A.A., Pautov, L.A. and Grew, E.S. (2002) The crystal chemistry of telyushenkoite and leifite, ANa6[Be2Al3Si15O39F2], A = Cs, Na. The Canadian Mineralogist, 40, 183192.
Sokolova, E., Hawthorne, F.C., Pautov, L.A., Agakhanov, A.A. and Karpenko, V.Yu. (2011) The crystal structure and crystal chemistry of mendeleevite-(Ce), Cs6(REE22Ca6)(Si70O175) (OH,F)14(H2O)21, a poten-tial microporous material. Mineralogical Magazine, 75, 25832596.
Uvarova, Y.A., Sokolova, E., Hawthorne, EC, Pautov, L.A. and Agakhanov, A.A. (2004) Anovel [Si8O45]18∼ sheet in the crystal structure of zeravshanite, Cs4Na2Zr3[Si18O45] (H2O)2 . The Canadian Mineralogist, 42, 125134.
Uvarova, Y.A., Sokolova, E., Hawthorne, F.C., Agakhanov, A. A, Pautov, L.A. and Karpenko, YY (2006) The crystal chemistry of senkevichite, CsKNaCa2TiO[Si7O18(OH)], from the Dara-i-Pioz Alkaline Massif, Northern Tajikistan. The Canadian Mineralogist, 44, 13411348.
Yefimov, A.F., Dusmatov, V.D., Ganzeyev, A.A. and Katayeva, Z.T (1971) Cesium kupletskite, a new mineral. Doklady of the Academy of Sciences U.S.S.R. Earth Sciences, 197, 140143.


Odigitriaite, CsNa5Ca5[Si14B2O38]F2, a new caesium borosilicate mineral from the Darai-Pioz alkaline massif, Tajikistan: Description and crystal structure

  • Atali A. Agakhanov (a1) (a2), Leonid A. Pautov (a2), Elena Sokolova (a3), Frank C. Hawthorne (a3), Vladimir Yu Karpenko (a1), Oleg I. Siidra (a1) and Vyacheslav A. Muftakhov (a1) (a4)...


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed