New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XII. Zubkovaite, Ca3Cu3(AsO4)4 | Mineralogical Magazine | Cambridge Core (original) (raw)

Abstract

The new mineral zubkovaite, Ca3Cu3(AsO4)4, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with anhydrite, svabite, hematite, johillerite, tilasite, fluorophlogopite, sanidine and aphthitalite. Zubkovaite occurs as coarse prismatic crystals up to 0.01 mm × 0.01 mm × 0.2 mm combined in radiating aggregates or crusts. The mineral is transparent, bright sky-blue, turquoise-coloured or light bluish-green, with vitreous lustre. It is brittle, with imperfect cleavage. The Mohs’ hardness is ca 3. Dcalc is 4.161 g cm–3. Zubkovaite is optically biaxial (–), α = 1.747(5), β = 1.774(5), γ = 1.792(5) and 2Vmeas = 75(10)°. Chemical composition (wt.%, electron microprobe) is: CaO 19.22, CuO 27.37, As2O5 52.54, SO3 0.67, total 99.80. The empirical formula based on 16 O apfu is Ca2.96Cu2.97(As3.945S0.07)Σ4.015O16. Zubkovaite is monoclinic, C2, a = 16.836(3), b = 5.0405(8), c = 9.1173(17) Å, β = 117.388(13)°, V = 687.0(2) Å3 and Z = 2. The strongest reflections of the powder XRD pattern [d,Å (I) (hkl)] are: 7.44 (100) ($\bar 2$01), 3.727 (79) (400, $\bar 2$02, $\bar 3$11), 3.334 (92) ($\bar 1$12), 2.914 (73) (311), 2.765 (50) ($\bar 6$01, $\bar 6$02), 2.591 (96) ($\bar 3$13) and 2.521 (53) (020). The crystal structure is unique for minerals. It was solved from single-crystal X-ray diffraction data to R = 7.19%. The structure contains trimers of Cu2+-centred polyhedra (consisting of one distorted square CuO4 in the core and two distorted square pyramids CuO5) and two crystallographically independent As5+O4 tetrahedra playing different roles: As(2)O4 tetrahedra link neighbouring trimers into ribbons whereas As(1)O4 tetrahedra link adjacent ribbons into heteropolyhedral layers; Ca cations are located in the interlayer space. The mineral is named in honour of the Russian crystallographer and crystal chemist Natalia Vital'evna Zubkova (born 1976).

References

Brese, N.E. and O'Keeffe, N.E. (1991) Bond-valence parameters for solids. Acta Crystallographica, 47, 192–197.CrossRefGoogle Scholar

Britvin, S.N., Dolivo-Dobrovolsky, D.V. and Krzhizhanovskaya, M.G. (2017) Software for processing the X-ray powder diffraction data obtained from the curved image plate detector of Rigaku RAXIS Rapid II diffractometer. Zapiski Rossiiskogo Mineralogicheskogo Obshchestva, 146, 104–107 [in Russian].Google Scholar

Fedotov, S.A. and Markhinin, Y.K. (editors) (1983) The Great Tolbachik Fissure Eruption. Cambridge University Press, New York, 341 pp.Google Scholar

Nespolo, M. and Ferraris, G. (2000) Twinning by syngonic and metric merohedry. Analysis, classification and effects on the diffraction pattern. Zeitschrift für Kristallographie, 215, 77–81.Google Scholar

Osterloh, D. and Müller-Buschbaum, H. (1994) Zur kenntnis eines Calcium-Kupfer-Orthoarsenats: Ca1.5Cu1.5(AsO4)2. Journal of Alloys and Compounds, 206, 155–158.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Lykova, I.S., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Yu. (2014 a) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. I. Yurmarinite, Na7(Fe3+,Mg,Cu)4(AsO4)6. Mineralogical Magazine, 78, 905–917.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Yu. (2014 b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. II. Ericlaxmanite and kozyrevskite, two natural modifications of Cu4O(AsO4)2. Mineralogical Magazine, 78, 1527–1543.Google Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Yu. (2015 a) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. III. Popovite, Cu5O2(AsO4)2. Mineralogical Magazine, 79, 133–143.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Belakovskiy, D.I., Yapaskurt, V.O., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Yu. (2015 b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. IV. Shchurovskyite, K2CaCu6O2(AsO4)4, and dmisokolovite, K3Cu5AlO2(AsO4)4. Mineralogical Magazine, 79, 1737–1753.CrossRefGoogle Scholar

Pekov, I.V., Yapaskurt, V.O., Britvin, S.N., Zubkova, N.V., Vigasina, M.F. and Sidorov, E.G. (2016 a) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. V. Katiarsite, KTiO(AsO4). Mineralogical Magazine, 80, 639–646.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Polekhovsky, Yu.S., Vigasina, M.F., Belakovskiy, D.I., Britvin, S.N., Sidorov, E.G. and Pushcharovsky, D.Yu. (2016 b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe3+O4(AsO4)4. Mineralogical Magazine, 80, 855–867.CrossRefGoogle Scholar

Pekov, I.V., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Zubkova, N.V. and Sidorov, E.G. (2017) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VII. Pharmazincite, KZnAsO4. Mineralogical Magazine, 81, 1001–1008.CrossRefGoogle Scholar

Pekov, I.V., Koshlyakova, N.N., Zubkova, N.V., Lykova, I.S., Britvin, S.N., Yapaskurt, V.O., Agakhanov, A.A., Shchipalkina, N.V., Turchkova, A.G. and Sidorov, E.G. (2018 a) Fumarolic arsenates – a special type of arsenic mineralization. European Journal of Mineralogy, 30, 305–322.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Yapaskurt, V.O., Chukanov, N.V., Belakovskiy, D.I., Sidorov, E.G. and Pushcharovsky, D.Yu. (2018 b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VIII. Arsenowagnerite, Mg2(AsO4)F. Mineralogical Magazine, 82, 877–888.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Belakovskiy, D.I., Vigasina, M.F., Yapaskurt, V.O., Sidorov, E.G., Britvin, S.N. and Pushcharovsky, D.Y. (2019 a) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. IX. Arsenatrotitanite, NaTiO(AsO4). Mineralogical Magazine, 83, 453–458.CrossRefGoogle Scholar

Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Ksenofontov, D.A., Pautov, L.A., Sidorov, E.G., Britvin, S.N., Vigasina, M.F. and Pushcharovsky, D.Yu. (2019 b) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. X. Edtollite, K2NaCu5Fe3+O2(AsO4)4, and alumoedtollite, K2NaCu5AlO2(AsO4)4. Mineralogical Magazine, 83, 485–495.CrossRefGoogle Scholar

Pekov, I.V., Lykova, I.S., Yapaskurt, V.O., Belakovskiy, D.I., Turchkova, A.G., Britvin, S.N., Sidorov, E.G. and Scheidl, K.S. (2019 c) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XI. Anatolyite, Na6(Ca,Na)(Mg,Fe3+)3Al(AsO4)6. Mineralogical Magazine, 83, 633–638.CrossRefGoogle Scholar

Sheldrick, G.M. (2015) Crystal structure refinement with SHELXL. Acta Crystallographica, C71, 3–8.Google Scholar

Symonds, R.B. and Reed, M.H. (1993) Calculation of multicomponent chemical equilibria in gas-solid-liquid systems: calculation methods, thermochemical data, and applications to studies of high-temperature volcanic gases with examples from Mount St. Helens. American Journal of Science, 293, 758–864.CrossRefGoogle Scholar