Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-25T18:23:29.566Z Has data issue: false hasContentIssue false
  • English
  • Français

Khvorovite, Pb2+4Ca2[Si8B2(SiB)O28]F, a new hyalotekite-group mineral from the Darai-Pioz alkaline massif, Tajikistan: Description and crystal structure

Published online by Cambridge University Press:  02 January 2018

Leonid A. Pautov ,
Atali A. Agakhanov ,
Elena Sokolova ,
Frank C. Hawthorne ,
Vladimir Y. Karpenko ,
Oleg I. Siidra ,
Viktor K. Garanin  and
Yassir A. Abdu
Leonid A. Pautov
Affiliation:
Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskii Pr-kt, 18-2, 119071 Moscow, Russia
Atali A. Agakhanov
Affiliation:
Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskii Pr-kt, 18-2, 119071 Moscow, Russia Department of Crystallography, St. Petersburg State University, University Embankment 7/9, 119034 St. Petersburg, Russia
Elena Sokolova*
Affiliation:
Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
Frank C. Hawthorne
Affiliation:
Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
Vladimir Y. Karpenko
Affiliation:
Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskii Pr-kt, 18-2, 119071 Moscow, Russia
Oleg I. Siidra
Affiliation:
Department of Crystallography, St. Petersburg State University, University Embankment 7/9, 119034 St. Petersburg, Russia
Viktor K. Garanin
Affiliation:
Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskii Pr-kt, 18-2, 119071 Moscow, Russia
Yassir A. Abdu
Affiliation:
Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Khvorovite, ideally Pb42+Ca2[Si8B2(SiB)O28]F, is a new borosilicate mineral of the hyalotekite group from the Darai-Pioz alkaline massif in the upper reaches of the Darai-Pioz river, Tajikistan. Khvorovite was found in a pectolite aggregate in silexites (quartz-rich rocks). The pectolite aggregate consists mainly of pectolite, quartz and fluorite, with minor aegirine, polylithionite, turkestanite and baratovite; accessory minerals are calcite, pyrochlore-group minerals, reedmergnerite, stillwellite-(Ce), pekovite, zeravshanite, senkevichite, sokolovaite, mendeleevite-(Ce), alamosite, orlovite, leucosphenite and several unknown Cs-silicates. Khvorovite occurs as irregular grains, rarely with square or rectangular sections up to 150 μm, and grain aggregates up to 0.5 mm. Khvorovite is colourless, rarely white, transparent with a white streak, has a vitreous lustre and does not fluoresce under ultraviolet light. Cleavage and parting were not observed. Mohs hardness is 5–5.5, and khvorovite is brittle with an uneven fracture. The measured and calculated densities are 3.96(2) and 3.968 g/cm3, respectively. Khvorovite is biaxial (+) with refractive indices (λ = 589 nm) α = 1.659(3), βcalc. = 1.671(2), γ = 1.676(3); 2Vmeas. = 64(3)°, medium dispersion: r < v. Khvorovite is triclinic, space group I1¯, a = 11.354(2), b = 10.960(2), c = 10.271(2) Å, α = 90.32(3), β = 90.00(3), γ = 90.00(3)°, V = 1278(1) Å3, Z = 2. The six strongest lines in the powder X-ray diffraction pattern [d (Å), I, (hkl)] are: 7.86, 100, (110); 7.65, 90, (101); 7.55, 90, (011); 3.81, 90, (202); 3.55, 90, (301); 2.934, 90, (312, 312). Chemical analysis by electron microprobe gave SiO2 36.98, B2O3 6.01, Y2O3 0.26, PbO 40.08, BaO 6.18, SrO 0.43, CaO 6.77, K2O 1.72, Na2O 0.41, F 0.88, O=F –0.37, sum 99.35 wt.%. The empirical formula based on 29 (O+F) a.p.f.u. is (Pb2.762+Ba0.62K0.56Na0.16)Σ4.10(Ca1.86Sr0.06Y0.04Na0.04)Σ2[Si8B2(Si1.46B0.65)Σ2.11O28](F0.71O0.29), Z = 2 , and the simplified formula is (Pb2+, Ba, K)4Ca2[Si8B2(Si,B)2O28]F. The crystal structure of khvorovite was refined to R1 = 2.89% based on 3680 observed reflections collected on a four-circle diffractometer with MoKα radiation. In the crystal structure of khvorovite, there are four [4]-coordinated Si sites occupied solely by Si with <Si–O>= 1.617 Å. The [4]-coordinated B site is occupied solely by B, with <B–O> = 1.478 Å. The [4]-coordinated T site is occupied by Si and B (Si1.46B0.54), with <T–O> = 1.605 Å; it ideally gives (SiB) a.p.f.u. The Si, B and T tetrahedra form an interrupted framework of ideal composition [Si8B2(SiB)O28]11–. The interstitial cations are Pb2+, Ba and K (minor Na) [A(11–22) sites] and Ca [M site]. The two A sites are each split into two subsites ∼0.5 Å apart and occupied by Pb2+ and Ba + K. The [8]-coordinated M site is occupied mainly by Ca, with minor Sr, Y and Na. Khvorovite is a Pb2+ analogue of hyalotekite, (Ba,Pb2+,K)4(Ca,Y)2[Si8(B,Be)2(Si,B)2O28]F and a Pb2+-, Ca-analogue of kapitsaite-(Y), (Ba,K)4(Y,Ca)2[Si8B2(B,Si)2O28]F. It is named after Pavel V. Khvorov (b. 1965), a Russian mineralogist, to honour his contribution to the study of the mineralogy of the Darai-Pioz massif.

Keywords

khvorovitenew mineral speciessilicatealkaline rocksDarai-Pioz massifTajikistanhyalotekiteelectron microprobe analysiscrystal structure
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 4 , August 2015 , pp. 949 - 963
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Agakhanov, A.A., Pautov, L.A., Karpenko, V.Y., 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, 523–529.CrossRefGoogle Scholar
Agakhanov, A.A., Pautov, L.A., Uvarova, Yu.A., Sokolova, E.V., Hawthorne, F.C. and Karpenko, V.Y. (2013) Laptevite-(Ce) NaFe2+(i-E7Ca5Y3) (SiO4)4(Si3B2PO18)(BO3)F11-new mineral of the vicanite group from the Darai-Pioz alkaline massif, Tajikistan. Novye Dannye o Mineralakh, 48, 5–11 [in Russian].Google Scholar
Belakovskiy, D.I. (1991) Die seltenen Mineralien von Dara-i-Pioz im Hochgebirge Tadshikistans. Lapis, 16(12), 42-48.Google Scholar
Chernitsova, N.M., Pudovkina, Z.V. and Pyatenko, Yu.A. (1982) About the crystal structure of tadzhikite ﹛(Ca,Tr)4(Y,Tr)2(Ti,Fe,Al)(O,OH)2[Si4B4O22]﹜. Soviet Physics Doklady, 27, 367–368.Google Scholar
Christy, A.G., Grew, E.S., Mayo, S.C., Yates, M.G. and Belakovskiy, D.I. (1998) Hyalotekite, (Ba,Pb,K)4(Ca,Y)2Si8(B,Be)2(Si,B)2O28F, a tectosilicate related to scapolite: new structure refinement, phase transitions and a short-range ordered 3b superstructure. Mineralogical Magazine, 62, 77–92.CrossRefGoogle Scholar
Cooper, M.A., Hawthorne, F.C. and Grew, E.S. (1998) Refinement of the crystal structure of tienshanite: short-range-order constrains on chemical composi-tion. The Canadian Mineralogist, 36, 1305–1310.Google Scholar
Dusmatov, V.D. (1968) On mineralogy of one alkaline massif. Pp. 134–135 in: Alkaline Rocks of Kirgizia and Kazakhstan. Ilym, Frunze [in Russian].Google Scholar
Dusmatov, V.D. (1971) Mineralogy of the Darai-Pioz Alkaline Massif (Southern Tien-Shan). PhD dissertation, Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements, Moscow, 171 pp. [in Russian].Google Scholar
Dusmatov, V.D., Efimov, A.F. and Semenov, E.I. (1963) The first find of a stillwellite in the USSR. Doklady Akademii NaukSSSR, 153(4), 913-915 [in Russian].Google Scholar
Dusmatov, V.D., Efimov, A.F., Alkhazov, V.Y., Kazakova, M.E. and Mumyatskaya, N.G. (1967a) Tienshanite, a new mineral. Doklady Akademii Nauk SSSR, 177, 678–680 [in Russian].Google Scholar
Dusmatov, V.D., Popova, N.A. and Kabanova, L.K. (1967b) The first find of reedmergnerite in the USSR. Doklady Akademii Nauk Tajikskoi SSR, 10(10), 51-53 [in Russian].Google Scholar
Dusmatov, V.D., Mogarovskiy, V.V. and Koreshina, Yu.B. (1972) Geochemistry of boron in granito-syenitic massifs of the Dara-i-Pioz River (southern Tien-Shan). Geokhimiya, 10, 722–732 [in Russian].Google Scholar
Efimov, A.F., Dusmatov, V.D., Alkhazov, Yu.A., Pudovkina, Z.G. and Kazakova, M.E. (1970) Tadzhikite—a new borosilicate of rare earths from the hellandite group. Doklady Akademii Nauk SSSR, 195(5), 1190-1193 [in Russian].Google Scholar
Faiziev, A.R., Gafurov, F.G. and Sharipov, B.N. (2010) Carbonatites of the Dara-i-Pioz Alkaline Massif, Central Tajikistan, and their compositional features. Geochemistry International, 48(11), 1084-1096.Google Scholar
Grew, E.S., Yates, M.G., Belakovskiy, D.I., Rouse, R.C. and Su, S-C. and Marquez, N. (1994) Hyalotekite from reedmergnerite-bearing peralkaline pegmatite, Dara-i-Pioz, Tajikistan and from Mn skarn, Langban, Varmland, Sweden: a new look at an old mineral. Mineralogical Magazine, 58, 285–297.CrossRefGoogle Scholar
Hawthorne, F.C, Cooper, M.A. and Taylor, M.C. (1998) Refinement of the crystal structure of tadzhikite. The Canadian Mineralogist, 36, 817–822.Google Scholar
Lindstrom, G. (1887) Om hyalotekit fran Langban. Ofversigt af Kongliga Vetenkaps-Akademiens Forhandlingar, 9, 589–593.Google Scholar
Malinovskii, Yu.A., Pobedimskaya, E.A. and Belov, N.V. (1977) Crystal structure of tienshanite. Soviet Physics Doklady, 22, 544–545.Google Scholar
Moore, P.B., Araki, T. and Ghose, S. (1982) Hyalotekite, a complex lead borosilicate: its crystal structure and the lone-pair effect of Pb(II). American Mineralogist, 67, 1012–1020.Google Scholar
Moskvin, A.V. (1937) Geography and geology of East Karategin. Pp. 682–739 in: Tadjik-Pamir Expedition of 1935. Akademiya Nauk SSSR, Moscow-Leningrad [in Russian].Google Scholar
Nordenskiold, A.E. (1877) Nya mineralier fran Langban. Geologiska Foreningens Forhandlingar, 3, 376–384.Google Scholar
Pautov, L.A., Khvorov, P.V., Sokolova, E.V., Ferraris, G., Ivaldi, G. and Bazhenova, L.F. (2000) Kapitsaite-(Y), (Ba,K)4(Y,Ca)2Si8(B,Si)4O28F-a new mineral. Zapiski Vserossiiskogo Mineralogicheskogo Obchshestva, 129(6), 42-49 [in Russian].Google Scholar
Pautov, L.A., Agakhanov, A.A., Sokolova, E. and Hawthorne, F.C. (2004) Maleevite, BaB2Si2O8, and pekovite, SrB2Si2O8, new mineral species from the Dara-i-Pioz alkaline massif, northern Tajikistan: description and crystal structure. The Canadian Mineralogist, 42, 107–120.CrossRefGoogle Scholar
Pautov, L.A., Agakhanov, A.A., Sokolova, E.V., Hawthorne, F.C. and Karpenko, V.Yu. (2011) Byzantievite, Ba5(Ca,.R££,Y)22(Ti,Nb)18(SiO4)4[(PO4),(SiO4)]4(BO3)9O21[(OH),F]43(H2O)1.5, a new mineral from the Darai-Pioz massif, Tajikistan. Novye Dannye o Mineralakh, 46, 5–12 [in Russian].Google Scholar
Pekov, I.V., Voloshin, A.V., Pushcharovskiy, D.Yu., Rastsvetaeva, R.K., Chukanov, N.V. and Belakovskiy, D.I. (2000) New data on calcybebor-osilite-(Y) (,R££,Ca)2(B,Be)2[SiO4]2(OH,O)2. Vestnik Moscowskogo Universiteta, ser. 4, Geologicheskaya, No. 2, 65–70 [in Russian].Google Scholar
Pouchou, J.L. and Pichoir, F. (1985) “PAP” (cpp) procedure for improved quantitative mieroanalysis. Pp. 104–106 in: Microbeam Analysis (Armstrong, J.T., editor). San Francisco Press, San Francisco, California, USA.Google Scholar
Rastsvetaeva, R.K., Pushcharovskii, D.Yu., Pekov, I.V. and Voloshin, A.V. (1996) Crystal structure of calcybeborosilite and its place in the datolite-gadolinite isomorphous series. Kristallografiya, 41, 235-239 [in Russian].Google Scholar
Reguir, E.P., Chakhmouradian, A.R. and Evdokimov, M.D. (1999) The mineralogy of a unique baratovite-and miserite-bearing quartz—albite—aegirine rock from the Dara-i-Pioz complex, northern Tajikistan. The Canadian Mineralogist, 37, 1369–1384.Google Scholar
Semenov, E.I., Dusmatov, V.D. and Samsonova, N.S. (1963) Yttrium-beryllium minerals of the datolite group. Kristallographia, 7(4), 677—679 (in Russian).Google Scholar
Semenov, E.I., Dusmatov, V.D. and Khomyakov, A.P. (1973) On the rare-earth miserite. Pp. 42-45 in: Mineralogicheskie Issledovania, 3. Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements, Moscow [in Russian].Google Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Ada Crystallographica, A32, 751–767.Google Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Ada Crystallographica, A64, 112–122.Google Scholar
Sokolova, E.V., Ferraris, G., Ivaldi, G., Pautov, L.A. and Khvorov, P.V. (2000) Crystal structure of kapitsaite-(Y), a new borosilicate isotypic with hyalotekite: Crystal chemistry of the related isomorphous series. Neues Jahrbuch fir Mineralogie—Monatshefte, 74-84.Google Scholar
Sokolova, E., Hawthorne, F.C, Pautov, L.A. and Agakhanov, A.A. (2010) Byzantievite, Ba5(Ca,i?££,Y)22(Ti,Nb)18(SiO4)4[(PO4),(SiO4)]4(BO3)9O21[(OH),F]43(H2O)1.5: the crystal structure and crystal chemistry of the only known mineral with oxyanions (BO3), (SiO4) and (PO4). Mineralogical Magazine, 74, 285–308.CrossRefGoogle Scholar
Uvarova, Yu.A., Sokolova, E., Hawthorne, F.C, Agakhanov, A.A., Karpenko, V.Yu. and Pautov, L.A. (2013) The crystal structure of laptevite-(Ce), NaFe2+(if£>£7Ca5Y3)(SiO4)4(Si3B2PO18)(BO3)F11, a new mineral species from the Darai-Pioz alkaline massif, Northern Tajikistan. Zeitschrift fiir Kristallographie—Crystalline Materials, 228, 550–557.Google Scholar
Wilson, AJ.C. (editor) (1992) International Tables for Crystallography, Volume C: Mathematical, Physical and Chemical Tables. Kluwer Academic Publishers, Dordrecht, The Netherlands.Google Scholar
Supplementary material: File

Pautov et al. supplementary material

CIF

Download Pautov et al. supplementary material(File)
File 61 KB
Supplementary material: File

Pautov et al. supplementary material

Structure factors

Download Pautov et al. supplementary material(File)
File 192.1 KB