Yaroshevskite, Cu9O2(VO4)4Cl2, a new mineral from the Tolbachik volcano, Kamchatka, Russia

2013 ◽  
Vol 77 (1) ◽  
pp. 107-116 ◽  
Author(s):  
I. V. Pekov ◽  
N. V. Zubkova ◽  
M. E. Zelenski ◽  
V. O. Yapaskurt ◽  
Yu. S. Polekhovsky ◽  
...  
Keyword(s):  
Direct Methods ◽  
Structural Formula ◽  
Scoria Cone ◽  
New Mineral ◽  
Indentation Hardness ◽  
State University ◽  
Calculated Density ◽  
X Ray ◽  
Reflected Light ◽  
Tolbachik Volcano

AbstractA new mineral, yaroshevskite, ideally Cu9O2(VO4)4Cl2, occurs in sublimates collected from the Yadovitaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with euchlorine, fedotovite, hematite, tenorite, lyonsite, melanothallite, atlasovite, kamchatkite and secondary avdoninite, belloite and chalcanthite. Yaroshevskite forms isolated prismatic crystals, up to 0.1 × 0.15 × 0.3 mm in size, on the surface of euchlorine crusts. The mineral is opaque and black, with a reddish black streak and lustre between metallic and adamantine. Yaroshevskite is brittle, no cleavage was observed and the fracture is uneven. The Mohs hardness is ~3½ (corresponding to a mean VHN micro-indentation hardness of 172 kg mm -2) and the calculated density is 4.26 g cm-3. In reflected light, yaroshevskite is grey with a weak bluish hue. Pleochroism, internal reflections and bireflectance were not observed. Anisotropy is very weak. The composition (wt.%) determined by electron microprobe is: CuO 61.82, ZnO 0.53, Fe2O3 0.04, V2O531.07, As2O50.32, MoO3 1.56, Cl 6.23, O=Cl2 1.41; total 100.16. The empirical formula, calculated on the basis of 20 (O + Cl) anions is (Cu8.80 Zn0.07 Fe0.01)Σ 8.88(V3.87Mo0.12As0.03)σ 4.02O18.01Cl1.99. Yaroshevskite is triclinic, space group P, a = 6.4344(11), b = 8.3232(13), c = 9.1726(16) Å , α = 105.338(14), β = 96.113(14), γ = 107.642(1)°, V = 442.05(13) Å3 and Z = 1. The nine strongest reflections in the X-ray powder pattern [dobs in Å (I)(hkl)] are as follows: 8.65(100)(001); 6.84(83)(01); 6.01(75)(100); 5.52(60)(01); 4.965(55)(011); 4.198(67)(1); 4.055(65)(110); 3.120(55)(021); 2.896(60)(21,003,20). The crystal structure was solved by direct methods from single-crystal X-ray diffraction data and refined to R = 0.0737. The yaroshevskite structure is unique. It is based on corrugated layers made up of chains of edge-sharing flat squares with central Cu2+ cations [Cu(1), Cu(4) and Cu(5)]; neighbouring chains are connected via groups consisting of three Cu2+ -centred squares [two Cu(3) and Cu(6)]. Neighbouring layers are connected via pairs of Cu(2)O4Cl five-coordinate polyhedra and isolated VO4 tetrahedra. The structure of yaroshevskite can also be considered in terms of oxygen-centred tetrahedra: O(7)Cu4 tetrahedra are connected via common Cu(4) and Cu(5) vertices to form pyroxene-like chains [O2Cu6]∞. In this context, the structural formula can be written Cu3[O2Cu6][VO4]4Cl2. The mineral name honours the Russian geochemist Alexei A. Yaroshevsky (b. 1934) of Moscow State University.

Majzlanite, K2Na(ZnNa)Ca(SO4)4, a new anhydrous sulfate mineral with complex cation substitutions from Tolbachik volcano

2019 ◽  
Vol 84 (1) ◽  
pp. 153-158 ◽  
Author(s):  
Oleg I. Siidra ◽  
Evgeny V. Nazarchuk ◽  
Anatoly N. Zaitsev ◽  
Vladimir V. Shilovskikh
Keyword(s):  
Complex Cation ◽  
Kamchatka Peninsula ◽  
Structural Formula ◽  
Scoria Cone ◽  
New Mineral ◽  
X Ray ◽  
Mineral Assemblages ◽  
Tolbachik Volcano ◽  
Cation Substitutions ◽  
Heteropolyhedral Framework

AbstractA new mineral majzlanite, ideally K2Na(ZnNa)Ca(SO4)4, was found in high-temperature exhalative mineral assemblages in the Yadovitaya fumarole, Second scoria cone of the Great Tolbachik Fissure Eruption (1975–1976), Tolbachik volcano, Kamchatka Peninsula, Russia. Majzlanite is associated closely with langbeinite and K-bearing thénardite. Majzlanite is grey with a bluish tint, has a white streak and vitreous lustre. The mineral is soluble in warm water. Majzlanite is monoclinic, C2/c, a = 16.007(2), b = 9.5239(11), c = 9.1182(10) Å, β = 94.828(7)°, V = 1385.2(3) Å3 and Z = 16. The eight strongest lines of the X-ray powder diffraction pattern are [d, Å (I, %)(hkl)]: 3.3721(40)($\bar{3}$12), 3.1473(56)($\bar{4}$02), 3.1062(65)($\bar{2}$22), 2.9495(50)($\bar{1}$31), 2.8736(100)($\bar{1}$13), 2.8350(70)(421), 2.8031(45)(511) and 2.6162(41)($\bar{5}$12). The following structural formula was obtained: K2Na(Zn0.88Na0.60Cu0.36Mg0.16)(Ca0.76Na0.24)(S0.98Al0.015Si0.005O4)4. The chemical composition determined by electron-microprobe analysis is (wt.%): Na2O 9.73, K2O 15.27, ZnO 11.20, CaO 7.03, CuO 4.26, MgO 1.07, Al2O3 0.47, SO3 51.34, SiO2 0.12, total 100.49. The empirical formula calculated on the basis of 16 O apfu is K1.99Na1.93Zn0.84Ca0.77Cu0.33Mg0.16(S3.94Al0.06Si0.01)O16 and the simplified formula is K2Na(Zn,Na,Cu,Mg)Σ2(Ca,Na)(SO4)4. No natural or synthetic compounds directly chemically and/or structurally related to majzlanite are known to date. The topology of the heteropolyhedral framework in majzlanite is complex. An interesting feature of the structure of majzlanite is an edge-sharing of ZnO6 octahedra with SO4 tetrahedra.

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe3+O4(AsO4)4

2016 ◽  
Vol 80 (5) ◽  
pp. 855-867 ◽  
Author(s):  
Igor V. Pekov ◽  
Natalia V. Zubkova ◽  
Vasiliy O. Yapaskurt ◽  
Yury S. Polekhovsky ◽  
Marina F. Vigasina ◽  
...  
Keyword(s):  
Kamchatka Peninsula ◽  
Scoria Cone ◽  
Structure Type ◽  
New Mineral ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Structure ◽  
Reflected Light ◽  
Tolbachik Volcano ◽  
Mohs Hardness

AbstractThe new mineral melanarsite, K3Cu7Fe3+O4(AsO4)4, was found in the sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka Peninsula, Russia. It is associated with dmisokolovite, shchurovskyite, bradaczekite, hematite, tenorite, aphthitalite, johillerite, arsmirandite, As-bearing orthoclase, hatertite, pharmazincite, etc. Melanarsite occurs as tabular to prismatic crystals up to 0.4 mm, separate or combined in clusters up to 1 mm across or in interrupted crusts up to 0.02 cm × 1 cm × 1 cm covering basalt scoria. The mineral is opaque, black, with a vitreous lustre. Melanarsite is brittle. Mohs' hardness is ∼4 and the mean VHN = 203 kg mm–2. Cleavage was not observed and the fracture is uneven. Dcalc is 4.39 g cm–3. In reflected light, melanarsite is dark grey. Bireflectance is weak, anisotropism is very weak. Reflectance values [R1–R2, % (λ, nm)] are 10.5–9.4 (470), 10.0–8.9 (546), 9.7–8.7 (589), 9.5–8.6 (650). The Raman spectrum is reported. Chemical composition (wt.%, electron microprobe) is K2O 10.70, CaO 0.03, CuO 45.11, ZnO 0.24, Al2O3 0.32, Fe2O3 6.11, TiO2 0.12, P2O5 0.07, As2O5 36.86, total 99.56. The empirical formula, based on 20 O apfu, is (K2.81Ca0.01)∑2.82(Cu7.02Fe3+0.95Al0.08Zn0.04Ti0.02)∑8.11(As3.97P0.01)∑3.98O20. Melanarsite is monoclinic, C2/c, a = 11.4763(9), b = 16.620(2), c = 10.1322(8) Å, β = 105.078(9)°, V = 1866.0(3) Å3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 9.22(100)(110), 7.59(35)(1₃11), 6.084(17) (111), 4.595(26)(1₃31, 220, 2₃21), 3.124(22)(3₃31, 1₃51), 2.763(20)(400, 1₃52), 2.570(23)(043) and 2.473(16) (260, 2₃61, 350). Melanarsite has a novel structure type. Its crystal structure, solved from single-crystal X-ray diffraction data (R = 0.091), is based upon a heteropolyhedral pseudo-framework built by distorted Cu(1–3)O6 and (Fe,Cu)O6 octahedra and As(1–3)O4 tetrahedra. Two crystallographically independent K+ cations are located in the tunnels and voids of the pseudo-framework centring eight- and seven-fold polyhedra. The name reflects the mineral being an arsenate and its black colour (from the Greek μέλαν, black).

Hrabákite, Ni9PbSbS8, a new member of the hauchecornite group from Příbram, Czech Republic

2021 ◽  
pp. 1-8
Author(s):  
Jiří Sejkora ◽  
Pavel Škácha ◽  
Jakub Plášil ◽  
Zdeněk Dolníček ◽  
Jana Ulmanová
Keyword(s):  
Czech Republic ◽  
Diffraction Data ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
X Ray ◽  
Reflected Light ◽  
Mohs Hardness ◽  
Cation Sites ◽  
The Ideal

Abstract The new mineral hrabákite (IMA2020-034) was found in siderite–sphalerite gangue with minor dolomite–ankerite at the dump of shaft No. 9, one of the mines in the abandoned Příbram uranium and base-metal district, central Bohemia, Czech Republic. Hrabákite is associated with Pb-rich tučekite, Hg-rich silver, stephanite, nickeline, millerite, gersdorffite, sphalerite and galena. The new mineral occurs as rare prismatic crystals up to 120 μm in size and allotriomorphic grains. Hrabákite is grey with a brownish tint. Mohs hardness is ca. 5–6; the calculated density is 6.37 g.cm–3. In reflected light, hrabákite is grey with a brown hue. Bireflectance is weak and pleochroism was not observed. Anisotropy under crossed polars is very weak (brownish tints) to absent. Internal reflections were not observed. Reflectance values of hrabákite in air (Rmin–Rmax, %) are: 39.6–42.5 at 470 nm, 45.0–47.5 at 546 nm, 46.9–49.2 at 589 nm and 48.9–51.2 at 650 nm). The empirical formula for hrabákite, based on electron-microprobe analyses (n = 11), is (Ni8.91Co0.09Fe0.03)9.03(Pb0.94Hg0.04)0.98(Sb0.91As0.08)0.99S7.99. The ideal formula is Ni9PbSbS8, which requires Ni 47.44, Pb 18.60, Sb 10.93 and S 23.03, total of 100.00 wt.%. Hrabákite is tetragonal, P4/mmm, a = 7.3085(4), c = 5.3969(3) Å, with V = 288.27(3) Å3 and Z = 1. The strongest reflections of the calculated powder X-ray diffraction pattern [d, Å (I)(hkl)] are: 3.6543(57)(200); 3.2685(68)(210); 2.7957(100)(211); 2.3920(87)(112); 2.3112(78)(310); 1.8663(74)(222); and 1.8083(71)(302). According to the single-crystal X-ray diffraction data (Rint = 0.0218), the unit cell of hrabákite is undoubtedly similar to the cell reported for tučekite. The structure contains four metal cation sites, two Sb (Sb1 dominated by Pb2+) and two Ni (with minor Co2+ content) sites. The close similarity in metrics between hrabákite and tučekite is due to similar bond lengths of Pb–S and Sb–S pairs. Hrabákite is named after Josef Hrabák, the former professor of the Příbram Mining College.

The new mineral insizwaite (PtBi2) and new data on niggliite (PtSn)

1972 ◽  
Vol 38 (299) ◽  
pp. 794-800 ◽  
Author(s):  
L. J. Cabri ◽  
D. C. Harris
Keyword(s):  
New Mineral ◽  
Indentation Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reflected Light ◽  
D 12 ◽  
Probable Space ◽  
Micro Indentation ◽  
Hardness Values ◽  
Reflectance Measurements

SummaryInsizwaite from Waterfall Gorge, Insizwa, is a new mineral with the composition Pt1·00Bi1·35Sb0·57. The name is for the locality and is to be applied to the end member PtBi2. The analysed material is an antimonian variety. The mineral is cubic, the unit-cell for the antimonian variety has a 6·625 (2) Å, probable space group Pa3, calc. D 12·8 g/cm3. The strongest lines on the X-ray diffraction powder pattern are: 2·96 (8) 210; 2·70 (8) 211; 2·34 (5) 220; 1·99 (10 311; 1·774 (7) 321; 1·433 (5) 421; 1·277 (6) 511, 333; 1·171 (6) 440; and 0·862 (7) 731. Under reflected light the mineral is white (in air and in oil) and is isotropic. Reflectance measurements at 470, 546, 589, and 650 nm gave 61·1, 60·0, 60·6, and 61·7 %. Micro-indentation hardness values range from 488 to 540 (av. 519) kg/mm2 with a 25 g load.New data are presented for niggliite from the type locality and for synthetic PtSn.

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. I. Yurmarinite, Na7(Fe3+,Mg,Cu)4(AsO4)6

2014 ◽  
Vol 78 (4) ◽  
pp. 905-917 ◽  
Author(s):  
I. V. Pekov ◽  
N. V. Zubkova ◽  
V. O. Yapaskurt ◽  
D. I. Belakovskiy ◽  
I. S. Lykova ◽  
...  
Keyword(s):  
Scoria Cone ◽  
Ore Deposits ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
X Ray ◽  
Tolbachik Volcano ◽  
Mohs Hardness ◽  
Heteropolyhedral Framework ◽  
Pale Green

AbstractA new mineral, yurmarinite, Na7(Fe3+,Mg,Cu)4(AsO4)6, occurs in sublimates of 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 hatertite, bradaczekite, johillerite, hematite, tenorite, tilasite and aphthitalite. Yurmarinite occurs as well-shaped, equant crystals up to 0.3 mm in size, their clusters up to 0.5 mm and thin, interrupted crystal crusts up to 3 mm × 3 mm on volcanic scoria. Crystal forms are {101}, {011}, {100}, {110} and {001}. Yurmarinite is transparent, pale green or pale yellowish green to colourless. The lustre is vitreous and the mineral is brittle. The Mohs hardness is ∼4½. One direction of imperfect cleavage was observed, the fracture is uneven. D(calc.) is 4.00 g cm−3. Yurmarinite is optically uniaxial (−), ω = 1.748(5), ε = 1.720(3). The Raman spectrum is given. The chemical composition (wt.%, electron microprobe data) is Na2O 16.85, K2O 0.97, CaO 1.28, MgO 2.33, MnO 0.05, CuO 3.17, ZnO 0.97, Al2O3 0.99, Fe2O3 16.44, TiO2 0.06, P2O5 0.12, V2O5 0.08, As2O5 56.68, total 99.89. The empirical formula, calculated on the basis of 24 O atoms per formula unit, is (Na6.55Ca0.28K0.22)S7.05(Fe2.483+Mg0.70Cu0.48Al0.23Zn0.14Ti0.01Mn0.01)S4.05(As5.94P0.02V0.01)S5.97O24. Yurmarinite is rhombohedral, Rc, a = 13.7444(2), c = 18.3077(3) Å, V = 2995.13(8) Å3, Z = 6. The strongest reflections in the X-ray powder pattern [d, Å (I)(hkl)] are: 7.28(45)(012); 4.375(33)(211); 3.440(35)(220); 3.217(36)(131,214); 2.999(30)(223); 2.841(100)(125); 2.598(43)(410). The crystal structure was solved from single-crystal X-ray diffraction data to R = 0.0230. The structure is based on a 3D heteropolyhedral framework formed by M4O18 clusters (M = Fe3+ > Mg,Cu) linked with AsO4 tetrahedra. Sodium atoms occupy two octahedrally coordinated sites in the voids of the framework. In terms of structure, yurmarinite is unique among minerals but isotypic with several synthetic compounds with the general formula (Na7–x☐x)(M3+x3+M1–x2+)(T5+O4)2 in which T = As or P, M3+ = Fe or Al, M2+ = Fe and 0 ≤ x ≤ 1. The mineral is named in honour of the Russian mineralogist, petrologist and specialist in studies of ore deposits, Professor Yuriy B. Marin (b. 1939). The paper also contains a description of the Arsenathaya fumarole and an overview of arsenate minerals formed in volcanic exhalations.

Hydroniumpharmacosiderite, a new member of the pharmacosiderite supergroup from Cornwall, UK: structure and description

2010 ◽  
Vol 74 (5) ◽  
pp. 863-869 ◽  
Author(s):  
S. J. Mills ◽  
A. R. Kampf ◽  
P. A. Williams ◽  
P. Leverett ◽  
G. Poirier ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Empirical Formula ◽  
Direct Methods ◽  
Structure Type ◽  
New Mineral ◽  
Calculated Density ◽  
X Ray ◽  
Mohs Hardness

AbstractHydroniumpharmacosiderite, ideally (H3O)Fe4(AsO4)3(OH)4·4H2O, is a new mineral from Cornwall, UK, probably from the St. Day group of mines. It occurs as a single yellowish green, slightly elongated cube, measuring 0.17 mm ×0.14 mm ×0.14 mm. The mineral is transparent with a vitreous lustre. It is brittle with a cleavage on {001}, has an irregular fracture, a white streak and a Mohs hardness of 2–3 (determined on H3O-exchanged pharmacosiderite). Hydroniumpharmacosiderite has a calculated density of 2.559 g cm–3 for the empirical formula. The empirical formula, based upon 20.5 oxygen atoms, is: [(H3O)0.50K0.48Na0.06]1.04(Fe3.79Al0.22)4.01[(As2.73P0.15)2.88O12](OH)4·4H2.14O. The five strongest lines in the X-ray powder diffraction pattern are [dobs(Å),Iobs,(hkl)]: 8.050,100,(001); 3.265,35,(112); 2.412,30,(113); 2.830,23,(202); 4.628,22,(111). Hydroniumpharmacosiderite is cubic, space group with a = 7.9587(2) Å, V = 504.11(2) Å3 and Z = 1. The crystal structure was solved by direct methods and refined to R1 = 0.0481 for 520 reflections with I > 2σ(I). The structure is consistent with determinations for H3O-exhchanged pharmacosiderite and the general pharmacosiderite structure type.

Feinglosite, a new mineral related to brackebuschite, from Tsumeb, Namibia

1997 ◽  
Vol 61 (405) ◽  
pp. 285-289 ◽  
Author(s):  
A. M. Clark ◽  
A. J. Criddle ◽  
A. C. Roberts ◽  
M. Bonardi ◽  
E. A. Moffatt
Keyword(s):  
Visible Spectrum ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
Indentation Hardness ◽  
Calculated Density ◽  
Reflected Light ◽  
The Mean ◽  
Micro Indentation ◽  
Reflectance Data ◽  
The Ideal

AbstractFeinglosite, the zinc analogue of arsenbrackebuschite, was found lining a cavity in a sample of massive chalcocite from Tsumeb, Namibia. In this cavity it is associated with wulfenite, anglesite and goethite. The mean of seven electron-microprobe analyses (wt.%) is: PbO 61.4, ZnO 7.3, FeO 1.8, As2O5 22.1, SO3 5.3, H2O (by difference) [2.1], total = [100.00]%, leading to the ideal formula: Pb2(Zn,Fe)[(As,S)O4]·H2O. Feinglosite is monoclinic, space group P21 or P21/m, a 8.973(6), b 5.955(3), c 7.766(6) Å, β 112.20(6)°, with Z = 2. The strongest five reflections of the X-ray powder diffraction pattern are [d in Å (I) (hkl)]: 4.85 (50) (110), 3.246 (100) (112), 2.988 (60) (301), 2.769 (60) (300/211), 2.107 (50) (321). The mineral is pale olive-green, transparent, sectile, and has a white streak and adamantine lustre. It overgrows clusters of goethite crystals and forms globular microcrystalline aggregates up to 0.5–0.75mm in size. The hardness on Mohs' scale is 4–5: the mean micro-indentation hardness is 263 at VHN100. Its calculated density is 6.52 g cm−3. The mineral is pale brownish grey in reflected light (when compared with goethite). Visible spectrum reflectance data are presented. Feinglosite is named for Mark N. Feinglos who first recognised the mineral on a specimen in his collection.

Unique thallium mineralization in the fumaroles of Tolbachik volcano, Kamchatka Peninsula, Russia. III. Evdokimovite, Tl4(VO)3(SO4)5(H2O)5

2014 ◽  
Vol 78 (7) ◽  
pp. 1711-1724 ◽  
Author(s):  
Oleg I. Siidra ◽  
Lidiya P. Vergasova ◽  
Yuri L. Kretser ◽  
Yuri S. Polekhovsky ◽  
Stanislav K. Filatov ◽  
...  
Keyword(s):  
Structural Information ◽  
Cinder Cone ◽  
Direct Methods ◽  
Kamchatka Peninsula ◽  
New Mineral ◽  
State University ◽  
X Ray Diffraction ◽  
The North ◽  
Tolbachik Volcano ◽  
The University

AbstractEvdokimovite, ideally Tl4(VO)3(SO4)5(H2O)5, was found in a fumarole of the 1st cinder cone of the North Breach of the Great Fissure Tolbachik volcano eruption of 1975–1976, Kamchatka Peninsula, Russia. Evdokimovite occurs as thin, colourless needles up to 0.09 mm long associated with shcherbinaite, pauflerite, bobjonesite, markhininite, karpovite and microcrystalline Mg, Al, Fe and Na sulfates. Evdokimovite is monoclinic, P21/n, a = 6.2958(14), b = 10.110(2), c = 39.426(11) Å , β = 90.347(6)º, V = 2509.4(10) Å3 and Z = 4 (from single-crystal diffraction data). The eight strongest lines of the powder X-ray diffraction pattern are (I/d/hkl): 57/9.793/011, 100/8.014/013, 26/6.580/006, 19/ 4.011/026, 29/3.621/118, 44/3.522/125, 19/3.010/036, 21/2.974/212. Chemical composition determined by the electron microprobe analysis is (wt.%): Tl2O 55.40, VO2 14.92, SO3 25.83, H2O 5.75, total 101.90. The empirical formula for evdokimovite calculated on the basis of (Tl + V + S) = 12 a.p.f.u. is Tl4.10V2.83S5.07H10.00O27.94. The simplified formula is Tl4(VO)3(SO4)5(H2O)5. The crystal structure was solved by direct methods and refined to R1 = 0.11 on the basis of 3660 independent observed reflections. V4+O6 octahedra and SO4 tetrahedra share common corners to form two types of vanadyl-sulfate chains, [(VO)(H2O)2(SO4)2]2– and [(VO)2(H2O)3(SO4)3]2–. Thallium atoms are located in between the chains. The structure can be described as a stacking of layers of two types, A and B. The A layer contains [(VO)2(H2O)3(SO4)3]2– chains and the Tl2 and Tl3 atoms, whereas the B layer contains [(VO)(H2O)2(SO4)2]2– chains and the Tl1 atoms. Stacking of the layers can be described as ...A’*BAA’B*A*..., where A and A’ denote A layers with opposite orientations of the [(VO)2(H2O)3(SO4)3]2– chains, and the A* and B* layers are rotated by 180º relative to the A and B layers, respectively. [(VO)2(H2O)3(SO4)3]2– chains are modulated and are arranged to form elliptical tunnels hosting disordered Tl(4), Tl(4A) and Tl(4B) sites. The new mineral is named in honour of Professor Mikhail Dmitrievich Evdokimov (1940–2010), formerly of the Department of Mineralogy, St Petersburg State University, for his contributions to mineralogy and petrology, and especially for teaching mineralogy to several generations of students at the University. Evdokimovite is the most complex V4+ sulfate known to date with structural information amounting to 1130 bits per unit cell, which places evdokimovite among minerals with the complexity of the vesuvianite group.

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VIII. Arsenowagnerite, Mg2(AsO4)F

2018 ◽  
Vol 82 (4) ◽  
pp. 877-888 ◽  
Author(s):  
Igor V. Pekov ◽  
Natalia V. Zubkova ◽  
Atali A. Agakhanov ◽  
Vasiliy O. Yapaskurt ◽  
Nikita V. Chukanov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Scoria Cone ◽  
New Mineral ◽  
Lemon Yellow ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Light Yellow ◽  
Tolbachik Volcano ◽  
Mohs Hardness

ABSTRACTA new mineral arsenowagnerite, Mg2(AsO4)F, the arsenate analogue of wagnerite, was found in sublimates of 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 closely with johillerite, tilasite, anhydrite, hematite, fluorophlogopite, cassiterite, calciojohillerite, aphthitalite and fluoborite. Arsenowagnerite occurs as equant to tabular crystals up to 1 mm across combined in interrupted crusts up to 0.1 cm × 1.5 cm × 3 cm. The mineral is transparent, light yellow, lemon-yellow, greenish-yellow or colourless and has a vitreous lustre. Arsenowagnerite is brittle, with Mohs hardness of ~5. Cleavage is distinct, the fracture is uneven. Dcalc = 3.70 g cm–3. Arsenowagnerite is optically biaxial (+), α = 1.614(2), β = 1.615(2), γ = 1.640(2) and 2Vmeas = 25(5)°. Wavenumbers of the strongest absorption bands in the IR spectrum (cm–1) are: 874, 861, 507, 491 and 470. The chemical composition (average of six electron-microprobe analyses, wt.%) is: MgO 38.72, CaO 0.23, MnO 0.32, CuO 0.60, ZnO 0.05, Fe2O3 0.11, TiO2 0.03, SiO2 0.08, P2O5 0.18, V2O5 0.03, As2O5 54.96, SO3 0.10, F 8.91 and –O=F –3.75, total 100.57. The empirical formula calculated on the basis of 5 (O + F) apfu is: (Mg1.98Cu0.02Mn0.01Ca0.01)Σ2.02(As0.99P0.01)Σ1.00O4.03F0.97. Arsenowagnerite is monoclinic, P21/c, a = 9.8638(3), b = 12.9830(3), c = 12.3284(3) Å, β = 109.291(3)°, V = 1490.15(7) Å3 and Z = 16. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 5.80(41)(002), 5.31(35)(120), 3.916(37)($\bar 2$21), 3.339(98)(221, 023), 3.155(65)(202), 3.043(100)($\bar 1$41), 2.940(72)($\bar 2$04), 2.879(34)($\bar 3$22) and 2.787(51)(320, $\bar 1$24). The crystal structure was solved from single-crystal X-ray diffraction data, R = 0.0485. Arsenowagnerite is isostructural to wagnerite-Ma2bc. The crystal structure is built by almost regular AsO4 tetrahedra, distorted MgO4F2 octahedra and distorted MgO4F trigonal bipyramids.

scholarly journals Tsygankoite, Mn8Tl8Hg2(Sb21Pb2Tl)Σ24S48, a New Sulfosalt from the Vorontsovskoe Gold Deposit, Northern Urals, Russia

2018 ◽  
Author(s):  
Anatoly V. Kasatkin ◽  
Emil Makovicky ◽  
Jakub Plášil ◽  
Radek Škoda ◽  
Atali A. Agakhanov ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Thick Layer ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
X Ray ◽  
Northern Urals ◽  
Reflected Light ◽  
Diffraction Peaks

Tsygankoite, ideally Mn8Tl8Hg2(Sb21Pb2Tl)Σ24S48, is a new sulfosalt discovered at the Vorontsovskoe gold deposit, Northern Urals, Russia. It occurs as lath-like elongated crystals up to 0.2 mm embedded in calcite-dolomite-clinochlore matrix. The associating minerals also include aktashite, alabandite, arsenopyrite, barite, cinnabar, fluorapatite, orpiment, pyrite, realgar, routhierite, sphalerite, tilasite, titanite, etc. The new mineral is non-fluorescent, black, opaque with a metallic lustre and black streak. It is brittle with an uneven fracture and no obvious parting and cleavage. Its Vickers hardness (VHN10) is 144 kg/mm2 (range 131–167) and its calculated density is 5.450 g cm-3. In reflected light tsygankoite is white; between crossed polars it is dark-grey to black. It is strongly anisotropic: rotation tints vary from light-grey to dark-grey to black. Pleochroism and internal reflections are not observed. The chemical composition of tsygankoite (wt.%, electron-microprobe data) is: Mn 6.29, Fe 0.02, Cu 0.02, Ag 0.01, Hg 5.42, Tl 26.05, Pb 5.84, As 3.39, Sb 30.89, S 21.87, Se 0.01, total 99.81. The empirical formula, calculated on the basis of 90 atoms pfu, is: Mn8.06Tl8.00(Hg1.90Fe0.03Cu0.02Ag0.01)Σ1.96(Sb17.85As3.18Pb1.98Tl0.97)Σ23.98(S48.00Se0.01)Σ48.01. Tsygankoite is monoclinic, space group C2/m, a = 21.362(4) Å, b = 3.8579(10) Å, c = 27.135(4) Å, β= 106.944(14)°, V = 2139.19(17) Å3 and Z = 1. The five strongest diffraction peaks from X-ray powder pattern [listed as (d,Å(I)(hkl)] are: 3.587(100)(112), 3.353(70)(-114), 3.204(88)(405), 2.841(72)(-513) and 2.786(99)(-514). The crystal structure of tsygankoite was refined from single-crystal X-ray diffraction data to R = 0.0607 and consists of an alternation of two thick layer-like arrays, one based on PbS-archetype and second – on SnS-archetype. Tsygankoite has been approved by the IMA-CNMNC under the number 2017-088. It is named for Mikhail V. Tsyganko, mineral collector from Northern Urals, who collected the samples where the new mineral was discovered.

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