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Ognitite, NiBiTe, a new mineral species, and Co-rich maucherite from the Ognit ultramafic complex, Eastern Sayans, Russia

  • Andrei Y. Barkov (a1), Luca Bindi (a2), Nobumichi Tamura (a3), Gennadiy I. Shvedov (a4), Björn Winkler (a5), Camelia V. Stan (a3), Wolfgang Morgenroth (a5), Robert F. Martin (a6), Federica Zaccarini (a7) and Christopher J. Stanley (a8)...


We describe the new species ognitite, NiBiTe, and a Co-rich variety of maucherite, hitherto unreported; both were discovered in the Ognit ultramafic complex of Neoproterozoic age in Eastern Sayans, Russia. The mean composition of ognitite (n = 7) is: Ni 17.05, Fe 0.07, Cu 0.14, Pd 0.14, Te 32.53, Bi 49.64, total 99.57 wt.%, corresponding to: (Ni1.11Cu0.008Fe0.005Pd0.005)Σ1.13Bi0.90Te0.97 (Σ atoms = 3 apfu). Ognitite is trigonal, space group P3m1 [R1 = 0.0276 for 81 reflections with Fo > 4σ(Fo)]. The unit-cell parameters derived from the single-crystal X-ray diffraction data are: a = 3.928(1) Å, c = 5.385(1) Å and V = 71.95(4) Å3, with Z = 1. The c:a ratio is 1.37. The powder X-ray diffraction data obtained on the same fragment used for the single-crystal study are: a = 3.9332(4) Å, c = 5.3920(6) Å and V = 72.24(1) Å3. Ognitite exhibits the brucite-type structure with edge-sharing NiTe3Bi3 octahedra forming sheets parallel to (0001). It is related to melonite, but is distinct compositionally by the extreme Bi-enrichment (melonite and its synthetic analogue contain <0.4 Bi apfu), and structurally as Bi and Te are ordered at two distinct sites, leading to the loss of the centre of symmetry in ognitite.

At more than 9 wt.% Co, or ~2 apfu Co, the core of Co-rich maucherite [(Ni,Co)11As8] in a zoned crystal, which is surrounded by Co-depleted orcelite, far surpasses the norm (≤1 and up to 3.9 wt.% Co). The unit-cell parameters of the Co-rich maucherite are: a = 6.85(2) and c = 21.83(5) Å, which are based on results of synchrotron micro-Laue diffraction.

The host rock consists of serpentine, clinochlore (Mg# 95–97) and skeletal chromite. We favour the metastable crystallisation of fluid-saturated globules of a sulfide–arsenide melt to explain the anomalous compositions of ore minerals at Ognit. These anomalies seem consistent with rapid cooling in a fluid-enriched system, possibly related to late-stage degassing of the magma, as reflected in a prominent metasomatic aureole at the contact with the enclosing gneissic rocks.


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*Author for correspondence: Andrei Y. Barkov, Email:


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Associate Editor: Irina O Galuskina



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Barkov, A.Y., Thibault, Y., Laajoki, K.V.O, Melezhik, V.A. and Nilsson, L.P. (1999) Zoning and substitutions in Co–Ni–(Fe)–PGE sulfarsenides from the Mount General'skaya layered intrusion, Arctic Russia. The Canadian Mineralogist, 37, 127142.
Barkov, A.Y., Nikiforov, A.A., Halkoaho, T.A.A. and Konnunaho, J.P. (2016) The origin of spheroidal patterns of weathering in the Pados-Tundra mafic-ultramafic complex, Kola Peninsula, Russia. Bulletin of the Geological Society of Finland, 88, 105113.
Barkov, A.Y., Shvedov, G.I., Flemming, R.L., Vymazalová, A. and Martin, R.F. (2017 a) Melonite from Kingash and Kuskanak, Eastern Sayans, Russia, and the extent of Bi-for-Te substitution in melonite and synthetic Ni(Te,Bi)2–x. Mineralogical Magazine, 81, 695705.
Barkov, A.Y., Nikiforov, A.A. and Martin, R.F. (2017 b) The structure and cryptic layering of the Pados-Tundra ultramafic complex, Serpentinite belt, Kola Peninsula, Russia. Bulletin of the Geological Society of Finland, 89, 3556.
Barkov, A.Y., Bindi, L., Winkler, B., Morgenroth, W., Shvedov, G.I., Martin, R.F., Zaccarini, F., Stan, C.V., Tamura, N. and Stanley, C.J. (2019) Ognitite, IMA 2018-006a. CNMNC Newsletter No. 47, February 2019, page 146; Mineralogical Magazine, 83, 143147.
Barnes, S.J. and Roeder, P. (2001) The range of spinel compositions in terrestrial mafic and ultramafic rocks. Journal of Petrology, 42, 22792302.
Bindi, L., Tredoux, M., Zaccarini, F., Miller, D.E. and Garuti, G. (2014) Non stoichiometric nickel arsenides in nature: the structure of orcelite, Ni5–xAs2 (x = 0.25), from the Bon Accord oxide body, South Africa. Journal of Alloys and Compounds, 601, 175178.
Cabri, L.J. and Laflamme, J.H.G. (1976) The mineralogy of the platinum-group elements from some copper-nickel deposits of the Sudbury area, Ontario. Economic Geology, 71, 11591195.
Ernst, R.E., Hamilton, M.A. and Soderlung, U. (2012) A proposed 725 Ma Dovyren–Kingash LIP of southern Siberia, and possible reconstruction link with 725–715 Ma Franklin LIP of North Laurentia. Abstract Volume, 35, GAC-MAC Joint Annual Meeting “Geoscience at the Edge” (May 27–29, 2012, St. Johns, Newfoundland and Labrador, Canada).
Fleet, M.E. (1973 a) The crystal structure of maucherite (Ni11As8). American Mineralogist, 58, 203210.
Fleet, M.E. (1973 b) The crystal structure of parkerite (Ni3Bi2S2). American Mineralogist, 58, 435439.
Fleet, M.E., Chryssoulis, S.L., Stone, E.S. and Weisener, C.G. (1993) Partitioning of platinum-group elements and Au in the Fe–Ni–Cu–S system: Experiments on the fractional crystallization of sulfide melt. Contributions to Mineralogy and Petrology, 115, 3644.
Garuti, G. and Rinaldi, R. (1986) Mineralogy of melonite-group and other tellurides from the Ivrea–Verbano basic complex, western Italian Alps. Economic Geology, 81, 12131217.
Gervilla, F., Makovicky, E., Makovicky, M. and Rose-Hansen, J. (1994) The system Pd–Ni–As at 790° and 450°C. Economic Geology, 89, 16301639.
Gervilla, F., Cabri, L.J., Kojonen, K., Sie, S.H., Papunen, H. and Hach-Alí, F.P. (2000) Trace platinum group elements in arsenides and sulfarsenides from magmatic ores: An electron microprobe and proton microprobe (micro-PIXE technique) study. Cadernos Lab. Xeoloxico de Laxe Coruna, 25, 103105.
Gladkochub, D.P., Wingate, M.T.D., Pisarevsky, S.A., Donskaya, T.V., Mazukabzov, A.M., Ponomarchuk, V.A. and Stanevich, A.M. (2006) Mafic intrusions in southwestern Siberia and implications for a Neoproterozoic connection with Laurentia. Precambrian Research, 147, 260278.
Gritsenko, Yu.D. and Spiridonov, E.M. (2008) Maucherite from metamorphic-hydrothermal assemblages of the Noril'sk ore field. Geology of Ore Deposits, 50, 590598.
Häkli, T.A., Vuorelainen, Y. and Sahama, T.G. (1965) Kitkaite (NiTeSe), a new mineral from Kuusamo, northeast Finland. American Mineralogist, 50, 581586.
Hattori, K., Takahashi, Y., Guillot, S. and Bo, Johanson (2005) Occurrence of arsenic (V) in forearc mantle serpentinites based on X-ray absorption spectroscopy study. Geochimica et Cosmochimica Acta, 69, 55855596.
Ishida, K. and Nishlzawa, T. (1990) The As–Co (arsenic–cobalt) system. Bulletin of Alloy Phase Diagrams, 11, 550554.
Makovicky, M., Makovicky, E., and Rose-Hansen, J. (1992) The phase system Fe–Pt–As–S at 850°C and 470°C. Neues Jahrbuch für Mineralogie, 10, 441453.
Makovicky, E. and Merlino, S. (2009) OD (order–disorder) character of the crystal structure of maucherite Ni8As11. European Journal of Mineralogy, 21, 855862.
Mekhonoshin, A.S., Tolstykh, N.D., Podlipsky, M.Yu., Kolotilina, T.B., Vishnevsky, A.V. and Benedyuk, Yu.P. (2013) PGE mineralization of dunite–wehrlite massifs at the Gutara-Uda interfluve, Eastern Sayan. Geology of Ore Deposits 55, 162175.
Mekhonoshin, A.S., Kolotilina, T.B. and Doroshkov, A.A. (2018) Geochemical model for the formation of the Medek platinum-bearing dunite-wehrlite intrusion (East Sayan, Russia). Russian Geology and Geophysics, 59, 16031615.
Oxford Diffraction (2006) CrysAlis RED (Version and ABSPACK in CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.
Özkurt, B. (2012) Effects of Ni substitution in Bi-2212 superconductors. Journal of Superconductivity and Novel Magnetism, 25, 17751779.
Peacock, M.A. and Thompson, R.M. (1946) On melonite from Quebec and the crystal structure of NiTe2. American Mineralogist, 31, 204.
Petruk, W., Harris, D.C. and Stewart, J.M. (1971) Characteristics of the arsenides, sulpharsenides and antimonides. The Canadian Mineralogist, 11, 150186.
Piña, R., Gervilla, F., Barnes, S.-J. and Lunar O.R. (2014) Liquid immiscibility between arsenide and sulfide melts: evidence from a LA–ICP–MS study in magmatic deposits at Serranía de Ronda (Spain). Mineralium Deposita, 50, 265279.
Prichard, H.M., Fisher, P.C., McDonald, I., Knight, R.D., Sharp, D.R. and Williams, J.P. (2013) The distribution of PGE and the role of arsenic as a collector of PGE in the Spotted Quoll nickel ore deposit in the Forrestania Greenstone Belt, Western Australia. Economic Geology, 108, 19031921.
Raič, S., Mogessie, A., Benkó, Z., Molnár, F., Hauck, S. and Severson, M. (2015) Arsenic-rich Cu-Ni-PGE mineralization in Wetlegs, Duluth complex, St. Louis county, Minnesota, USA. The Canadian Mineralogist, 53, 105132.
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112122.
Shvedov, G.I. and Barkov, A.Y. (2017) Primary and alteration assemblages of platinum-group minerals from the Ognit complex, Irkutskaya oblast, Eastern Sayans, Russia. Neues Jahrbuch für Mineralogie Abhandlungen: Journal of Mineralogy and Geochemistry, 194, 3548.
Singleton, M. and Nash, P. (1987) The As–Ni (arsenic–nickel) system. Journal of Phase Equilibria, 8, 419422.
Tamura, N. (2014) XMAS: A Versatile Tool for Analyzing Synchrotron X-ray Microdiffraction Data. Pp. 125155 in: Strain and Dislocation Gradients from Diffraction (Barabash, R. and Ice, G., editor). Imperial College Press, London, UK.
Tolstykh, N.D., Polyakova, G.V., Izokh, A.E., Podlipsky, M.Yu., Mekhonoshin, A.S., Orsoev, D.A. and Kolotilina, T.B. (2014) Cu–Ni–PGE deposits of east Siberia hosted by Neoproterozoic mafic-ultramafic complexes. Pp. 138–140 in: Abstract Volume 2014 Convention 11th International Conference on Gondwana to Asia 20–21 September, Beijing, China IAGR Conference Series No. 20.
Wagner, T. and Lorenz, J. (2002) Mineralogy of complex Co–Ni–Bi vein mineralization, Bieber deposit, Spessart, Germany. Mineralogical Magazine, 66, 385407.
Wilson, A.J.C., Ed. (1992) International Tables for Crystallography, Volume C: Mathematical, Physical and Chemical Tables. Kluwer Academic, Dordrecht, NL.
Yilmaz, F., Kilicaslan, M.F., Atanur, O.M., Hong, S.-J. and Uzun, O. (2012) Effects of substitution of Al and Bi for Ni on structure and hydrogen storage properties of LaNi4.7–xAl0.3Bix (x = 0.1, 0.2, 0.3) alloy. Japanese Journal of Applied Physics, 51, 09MB01.
Yund, R.A. (1961) Phase relations in the system Ni–As. Economic Geology, 56, 12731296.


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