Hostname: page-component-76fb5796d-x4r87 Total loading time: 0 Render date: 2024-04-26T11:47:14.229Z Has data issue: false hasContentIssue false
  • English
  • Français

Falgarite, K4(VO)3(SO4)5, a new mineral from sublimates of a natural underground coal fire at the tract of Kukhi-Malik, Fan-Yagnob coal deposit, Tajikistan

Published online by Cambridge University Press:  01 April 2020

Leonid A. Pautov ,
Mirak A. Mirakov ,
Oleg I. Siidra Open the ORCID record for Oleg I. Siidra [Opens in a new window] ,
Abdulkhak R. Faiziev ,
Еvgeny V. Nazarchuk ,
Vladimir Yu. Karpenko  and
Saimudasir Makhmadsharif
Leonid A. Pautov
Affiliation:
Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy pr. 18-2, 119071Moscow, Russia Institute of Mineralogy UB RAS, Miass, Chelyabinsk district, 456317, Russia
Mirak A. Mirakov
Affiliation:
Institute of Geology, Earthquake Engineering and Seismology, Academy of Sciences of the Republic of Tajikistan, Aini 267, 734063, Dushanbe, Tajikistan
Oleg I. Siidra*
Affiliation:
Department of Crystallography, St. Petersburg State University, University Emb., 7/9, St. Petersburg, 119034, Russia Kola Science Center, Russian Academy of Sciences, Apatity, Murmansk Region, 184200 Russia, 683006, Russia
Abdulkhak R. Faiziev
Affiliation:
Institute of Geology, Earthquake Engineering and Seismology, Academy of Sciences of the Republic of Tajikistan, Aini 267, 734063, Dushanbe, Tajikistan
Еvgeny V. Nazarchuk
Affiliation:
Department of Crystallography, St. Petersburg State University, University Emb., 7/9, St. Petersburg, 119034, Russia
Vladimir Yu. Karpenko
Affiliation:
Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy pr. 18-2, 119071Moscow, Russia
Saimudasir Makhmadsharif
Affiliation:
Institute of Geology, Earthquake Engineering and Seismology, Academy of Sciences of the Republic of Tajikistan, Aini 267, 734063, Dushanbe, Tajikistan
*
*Author for correspondence: Oleg I. Siidra, Email: o.siidra@spbu.ru
Get access Rights & Permissions [Opens in a new window]

Abstract

A new mineral falgarite, K4(V+4O)3(SO4)5 was discovered at the tract of Kukhi-Malik, Fan-Yagnob coal deposit, ca. 75 km N of Dushanbe, Tajikistan. The new mineral is named after the Falgar, an ancient Sogdian name for an area around the Zeravshan riverhead. Falgarite is a fumarolic mineral formed directly from a gas emitted by a natural underground coal fire. Associated minerals are anhydrite, baryte, molybdite, an unidentified Tl-vanadyl sulfate, K–Mg sulfate and an anhydrous Mg-sulfate. Falgarite forms small isometric or pseudo-octahedral individual crystals (10–60 μm) of turquoise colour and spherical aggregates up to 0.5 mm in diameter. Mohs hardness is ~ 2.5, Dmeas = 2.87(2) and Dcalc = 2.89 g/cm3. Refractive indices are: α = 1.588(3), β(calc.) = 1.600(3) and γ = 1.609(2) (590 nm). In transmitted light falgarite is transparent green with a weak pleochroism. The mineral is non-soluble in H2O and 5% HNO3 at room temperature. Infrared spectra support the absence of H2O and OH–. The chemical composition determined by electron-microprobe analysis is (wt.%): Na2O 0.55, K2O 20.76, Tl2O 1.83, VO2 29.38 and SO3 46.78, total 99.29. The empirical formula (based on 23 O apfu) is: (K3.76Na0.15Tl0.07)Σ3.98V3.02S4.99O23.0. The strongest lines of the powder X-ray diffraction pattern are [d,Å(I,%)(hkl)]: 3.20(70)(202); 3.17(80)024; 3.14(70)$\bar{2}$04; 3.01(50)$\bar{1}$51; and 2.88(100)151. Falgarite is monoclinic, P21/n, a = 8.7209(5), b = 16.1777(6), c = 14.4614(7) Å, β = 106.744(5)°, V = 1953.77(17) Å3, Z = 4 and R1 = 0.05. VO6 octahedra and SO4 tetrahedra link together by sharing corners thus forming a [(VO)3(SO4)5]4– framework. K+, Na+ and Tl+ cations are located in the channels of the framework. The synthetic K4(VO)3(SO4)5 analogue is known.

Keywords

falgariteanhydrous sulfatesexhalative mineralscoal firesfumarolesKukhi-MalikRavat
Type
Article
Information
Mineralogical Magazine , Volume 84 , Issue 3 , June 2020 , pp. 455 - 462
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland, 2020

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.)

Footnotes

Associate Editor: David Hibbs

References

Belakovski, D. (1990) Die Mineralien der brennenden Kohleflöze von Ravat in Tadshikistan. Lapis, 15, 21–26.Google Scholar
Belakovskiy, D.I. and Moskalev, I.V. (1988) Ammonia nitrate in products of coal combustion in the Kukhi-Malik valley (Central Tajikistan). Novye dannye o mineralakh, 35, 191–194 [in Russian].Google Scholar
Belakovskiy, D.I., Novikov, V.P., Pautov, L.A. and Suprychev, V.V. (1988) The first find of letovicite on the territory of the USSR (the Central Tajikistan). Doklady Tadzhikskoi Akademii nauk, 31, 603–606 [in Russian].Google Scholar
Ermakov, N.P. (1935) Pasrud-Yagnobskoye coal deposit and coal-seam fires of the Kan-Tag mountain. Pp. 47–66 in: On the Geology of the Coal Deposits of Tajikistan. Materials of Tadjik-Pamir Expedition, XII [in Russian].Google Scholar
Fehrmann, R., Boghosian, S., Papatheodorou, G.N., Nielsen, K., Berg, R.W. and Bjerrum, N.J. (1989) Crystal structure and infrared and Raman spectra of potassium vanadyl sulfate K4(VO)3(SO4)5. Inorganic Chemistry, 28, 1847–1853.CrossRefGoogle Scholar
Krivovichev, S.V., Vergasova, L.P., Britvin, S.N., Filatov, S.K., Kahlenberg, V. and Ananiev, V.V. (2007) Pauflerite, β-(VO(SO4)), a new mineral species from the Tolbachik volcano, Kamchatka peninsula, Russia. The Canadian Mineralogist, 45, 921–927.CrossRefGoogle Scholar
Mandarino, J.A. (2005) Derivation of a new Gladstone-Dale constant for VO2. The Canadian Mineralogist, 43, 1123–1124.CrossRefGoogle Scholar
Mirakov, M.A., Faiziev, A.R. and Pautov, L.A. (2017) Native selenium in products of the underground fire of the Fan-Yagnob coal field (the Central Tajikistan). Doklady Akademii nauk Respubliki Tadzhikistan, 60, 456–460 [in Russian with English abstract].Google Scholar
Mirakov, M.A., Pautov, L.A., Karpenko, V.Yu., Faiziev, A.R. and Mahmadsharif, S. (2019) Pauflerite β-VO(SO4) from sublimations of the natural underground coal fire at the Kukhi-Malik tract, Fan-Yagnob coal deposit, Tajikistan. New data on minerals, 53, 114–121 [in Russian with English abstract].Google Scholar
Nasdala, L. and Pekov, I.V. (1993) Ravatite, C14H10, a new organic mineral species from Ravat, Tadzhikistan. European Journal of Mineralogy, 5, 699–705.CrossRefGoogle Scholar
Novikov, V.P. and Suprychev, V.V. (1986) Conditions of the modern mineral genesis at the underground coal fires at Fan-Yagnobskoye deposit. Mineralogia Tadzhikistana, 7, 91–104 [in Russian with English abstract].Google Scholar
Novikov, V.P., Suprychev, V.V. and Babaev, M.A. (1979). Sal ammoniac from the underground fire sublimates at the Ravat coal deposit (Central Tajikistan). Doklady Akademii nauk Tadjikskoi SSR, 22(11), 687–691 [in Russian].Google Scholar
Novikov, V.P., Suprychev, V.V. and Salikhov, F.S. (1989) Some geochemical features of hypergenic mineral formation in a modern coal fire (for example, the Fan-Yagnob deposit). Mineralogia Tadzhikistana, 8, 107–118 [in Russian with English abstract].Google Scholar
Okhunov, R.V., Yorov, Z.Yo. and Negmatov, I.I. (2017) Atlas reference book of the Fan-Yagnob coal deposit. Dushanbe, 170 p. [in Russian].Google Scholar
Pautov, L.A., Mirakov, M.A., Siidra, O.I., Nazarchuk, Е.V., Faiziev, A.R. and Karpenko, V.Y. (2018) Falgarite, IMA 2018-069. CNMNC Newsletter No. 45, October 2018, page 1231; Mineralogical Magazine, 82, 1225–1232.Google Scholar
Pautov, L.A., Mirakov, M.A., Mahmadsharif, S., Karpenko, V.Yu. and Faiziev, A.R. (2019) A finding of a native tellurium in sublimations of the natural underground fire at the Kukhi-Malik tract at the Fan-Yagnob coal deposit (Tajikistan). New data on minerals, 53, 95–99 [in Russian with English abstract].Google Scholar
Sharygin, V.V., Sokol, E.V. and Belakovski, D.I. (2009) Fayalite–sekaninaite paralava from the Ravat coal fire (central Tajikistan). Russian Geology and Geophysics, 50, 703–721.CrossRefGoogle Scholar
Sharygin, V.V., Sokol, E.V., Belakovsky, D.I. (2014) Mineralogy and origin of fayalite- sekaninaite paralava: Ravat coal fire, Central Tajikistan. Pp. 581–607 in: Coal and Peat Fires: A Global Perspective, V. 3 – Case studies - Coal fires (Stracher, G.B., Prakash, A. and Sokol, E.V., editors). 2014, Elsevier B.V.Google Scholar
Schindler, M., Hawthorne, F.C. and Baur, W.H. (2000) Crystal-chemical aspects of vanadium: polyhedral geometries, characteristic bond valences and polymerization of (VOn) polyhedra. Chemistry of Materials, 12, 1248–1259.CrossRefGoogle Scholar
Shchukin, I.S. (1936) General sketch of Tajikistan. Pp. 7–86 in: Tajikistan (physiographic sketch). Report on the Tajik-Pamir expedition in 1933. Issue XXIII, Tajik-Pamir Expedition, Leningrad [in Russian].Google Scholar
Sheldrick, G.M. (2015) Crystal structure refinement with SHELXL. Acta Crystallographica, C71, 3–8.Google Scholar
Smirnov, Yu.M. (2011) Eternal fire of Mitre and Fan-Yagnob coal fire. Idnakar: methods of historical and cultural reconstruction, 1, 10–44 [in Russian with English Abstract].Google Scholar
Sokol, E.V., Maksimova, N.V., Nigmatulina, E.N., Sharygin, V.V. and Kalugin, V.M. (2005) Pyrogeniс metamorphism. Izd-vo SB RAS, Novosibirsk, Russia, 284 pp. [in Russian].Google Scholar
Vadilo, P.S. (1958). An underground fire in Central Tajikistan. Priroda, 8, 88–91.Google Scholar
Supplementary material: File

Pautov et al. supplementary material

Pautov et al. supplementary material 1

Download Pautov et al. supplementary material(File)
File 529 KB
Supplementary material: PDF

Pautov et al. supplementary material

Pautov et al. supplementary material 2

Download Pautov et al. supplementary material(PDF)
PDF 214.7 KB