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PlaSIl J.,ASCR Institute of Physics Prague | Kasatkin A.V.,V O Almazjuvelirexport | SKoda R.,Masaryk University | Skacha P.,Mining Museum Pribram | Skacha P.,Charles University
Mineralogical Magazine | Year: 2014

Klajite, MnCu4(AsO4)2(AsO3OH)2(H2O)10, the Mn-Cu-bearing member of the lindackerite group, was found in Jáchymov, Czech Republic, as the second world occurrence. It is associated with ondrus?ite and other arsenate minerals growing on the quartz gangue with disseminated primary sulfides, namely tennantite and chalcopyrite. Electron-microprobe data showed klajite aggregates to be chemically inhomogeneous at larger scales, varying from Mn-Ca-rich to Cu-rich domains. The chemical composition of the the Mn-rich parts of aggregates can be expressed by the empirical formula (Mn0 . 4 6Ca0 . 2 2Cu0 . 07Mg0 . 0 2 )S 0 . 7 7(Cu3 . 8 2Mg0 . 1 4Ca0 . 0 3Zn0 . 0 1 ) S4 . 00(As1 . 94Si0 . 06)S 2 . 0 0 O8[AsO2.73(OH)1.27]2(H 2O)10 (mean of seven representative spots; calculated on the basis of As + Si + P = 4 a.p.f.u. (atoms per formula unit) and 10 H2O from ideal stoichiometry), showing a slight cationic deficiency at the key Me-site. According to single-crystal X-ray diffraction, klajite from Jáchymov is triclinic, P1- , with a = 6.4298(8), b = 7.9716(8), c = 10.707(2) Å , a = 85.737(12)°, b = 80.994(13)°, g = 84.982(10)°, and V = 538.85(14) Å 3, Z = 1. The crystal structure was refined to R1 = 0.0628 for 1034 unique observed reflections (with Iobs > 3s(I)), confirming that klajite (Mn-Cu member) and ondrus?ite (Ca-Cu member) are isostructural. The current data-set allowed determination of the positions of several hydrogen atoms. Discussion on hydrogen bonding networks in the structure of klajite as well as detailed bond-valence analysis are provided. © 2014 The Mineralogical Society. Source

Kasatkin A.V.,V O Almazjuvelirexport | Nestola F.,University of Padua | Plasil J.,ASCR Institute of Physics Prague | Marty J.,5199 East Silver Oak Road | And 10 more authors.
Mineralogical Magazine | Year: 2013

Two new minerals - manganoblodite (IMA2012-029), ideally Na 2Mn(SO4)2·4H2O, and cobaltoblodite (IMA2012-059), ideally Na2Co(SO4) 2·4H2O, the Mn-dominant and Co-dominant analogues of blodite, respectively, were found at the Blue Lizard mine, San Juan County, Utah, USA. They are closely associated with blodite (Mn-Co-Ni-bearing), chalcanthite, gypsum, sideronatrite, johannite, quartz and feldspar. Both new minerals occur as aggregates of anhedral grains up to 60 mm (manganoblodite) and 200 mm (cobaltoblodite) forming thin crusts covering areas up to 2×2 cm on the surface of other sulfates. Both new species often occur as intimate intergrowths with each other and also with Mn-Co-Ni-bearing blodite. Manganoblödite and cobaltoblodite are transparent, colourless in single grains and reddish-pink in aggregates and crusts, with a white streak and vitreous lustre. Their Mohs' hardness is ∼21/2. They are brittle, have uneven fracture and no obvious parting or cleavage. The measured and calculated densities are Dmeas = 2.25(2) g cm-3 and D calc = 2.338 g cm-3 for manganoblodite and D meas = 2.29(2) g cm-3 and Dcalc = 2.347 g cm-3 for cobaltoblodite. Optically both species are biaxial negative. The mean refractive indices are a = 1.493(2), β = 1.498(2) and γ = 1.501(2) for manganoblodite and a = 1.498(2), β = 1.503(2) and γ = 1.505(2) for cobaltoblodite. The chemical composition of manganoblodite (wt.%, electron-microprobe data) is: Na2O 16.94, MgO 3.29, MnO 8.80, CoO 2.96, NiO 1.34, SO3 45.39, H2O (calc.) 20.14, total 98.86. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na1 9 6(Mn0.44Mg0.29Co0.14Ni0.06)Σ0. 93S2.03O8·4H2O. The chemical composition of cobaltoblodite (wt.%, electron-microprobe data) is: Na2O 17.00, MgO 3.42, MnO 3.38, CoO 7.52, NiO 2.53, SO3 45.41, H2O (calc.) 20.20, total 99.46. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na1.96(Co0.36Mg0.30Mn 0.17Ni0.12)Σ0.95S2.02O 8·4H2O. Both minerals are monoclinic, space group P21/a, with a = 11.137(2), b = 8.279(1), c = 5.5381(9) Å, β = 100.42(1)°, V = 502.20(14) Å3 and Z = 2 (manganoblödite); and a = 11.147(1), b = 8.268(1), c = 5.5396(7) Å, β = 100.517(11)°, V = 501.97(10) Å3 and Z = 2 (cobaltoblödite). The strongest diffractions from X-ray powder pattern [listed as (d,Å (I)(hkl)] are for manganoblödite: 4.556(70)(210, 011); 4.266(45)(2̄01); 3.791(26)(2̄11); 3.338(21)(310); 3.291(100)(220, 021), 3.256(67)(211, 1̄21), 2.968(22)(2̄21), 2.647(24)(4̄01); for cobaltoblödite: 4.551(80)(210, 011); 4.269(50)(2̄01); 3.795(18)(2̄11); 3.339(43)(310); 3.29(100)(220, 021), 3.258(58)(211, 1̄21), 2.644(21)(4̄01), 2.296(22)(1̄22). The crystal structures of both minerals were refined by single-crystal X-ray diffraction to R1 = 0.0459 (manganoblödite) and R1 = 0.0339 (cobaltoblödite). © 2013 The Mineralogical Society. Source

Chukanov N.V.,RAS Institute of Problems of Chemical Physics | Britvin S.N.,Saint Petersburg State University | Mohn G.,J. Wittemannstrasse 5 | Pekov I.V.,Moscow State University | And 4 more authors.
Mineralogical Magazine | Year: 2015

The new mineral shilovite, the first natural tetrammine copper complex, was found in a guano deposit located on the Pabellón de Pica Mountain, near Chanabaya, Iquique Province, Tarapacá Region, Chile. It is associated with halite, ammineite, atacamite (a product of ammineite alteration) and thénardite. The gabbro host rock consists of amphibole, plagioclase and minor clinochlore, and contains accessory chalcopyrite. The latter is considered the source of Cu for shilovite. The new mineral occurs as deep violet blue, imperfect, thick tabular to equant crystals up to 0.15 mm in size included in massive halite. The mineral is sectile. Its Mohs hardness is 2. Dcalc is 1.92 g cm-3. The infrared spectrum shows the presence of NH3 molecules and NO3 anions. Shilovite is optically biaxial (+), α = 1.527(2), β = 1.545(5), γ = 1.610(2). The chemical composition (electron-microprobe data, H calculated from ideal formula, wt.%) is Cu 26.04, Fe 0.31, N 30.8, O 35.95, H 4.74, total 100.69. The empirical formula is H12.56(Cu1.09Fe0.01)N5.87O6.00. The idealized formula is Cu(NH3)4(NO3)2. The crystal structure was solved and refined to R = 0.029 based upon 2705 unique reflections having F > 4σ(F). Shilovite is orthorhombic, space group Pnn2, a = 23.6585(9), b = 10.8238(4), c = 6.9054(3) Å, V = 1768.3(1) Å3, Z = 8. The strongest reflections of the powder X-ray diffraction pattern [d, Å (I,%) (hkl)] are: 5.931 (41) (400), 5.841 (100) (011), 5.208 (47) (410), 4.162 (88) (411), 4.005 (62) (420), 3.462 (50) (002), 3.207 (32) (031), 2.811 (40) (412). © 2015 Mineralogical Society. Source

Plasil J.,ASCR Institute of Physics Prague | Sejkora J.,National Museum | Skoda R.,Masaryk University | Novak M.,Masaryk University | And 5 more authors.
Mineralogical Magazine | Year: 2014

Hlousekite, (Ni,Co)Cu4(AsO4)2(AsO3OH)2(H2O)9, is a new supergene arsenate mineral from the Geister vein (Rovnost mine), Jáchymov (St Joachimsthal), Western Bohemia, Czech Republic. It was found along with veselovskyite, pradetite, lavendulan, arsenolite, babanekite and gypsum on the surface of strongly altered ore fragments containing dominant tennantite and chalcopyrite. Hlousekite forms thin, lath-like crystals, locally elongated reaching up to 3 mm across. It is transparent, has a pale green colour with vitreous lustre, has a greyish-white streak and it is very brittle with an uneven fracture. It does not fluoresce under shortwave or longwave ultraviolet radiation. Cleavage on {010} is perfect; the Mohs hardness is 2-3. The calculated density is 3.295 g cm-3. Hlousekite is optically biaxial with α′ = 1.653(2) and γ′ = 1.73. The estimated optical orientation is γ′ vs. elongation (c) = 14(1)°. In larger grains it is weakly to moderately pleochroic (α = colourless, γ = pale green to green). Hloušekite is triclinic, space group P1¯, a = 6.4010(6), b = 8.0041(6), c = 10.3969(14) å, α = 85.824(8), b = 79.873(9), γ = 84.655(7)° and V = 521.23(10) å3, with Z = 1, a:b:c = 0.800:1:1.299. The eight strongest lines in the powder X-ray diffraction (XRD) pattern [d in å (I)(hkl)] are 10.211(100)(001), 7.974(9)(010), 3.984(6)(020), 3.656(5)(11¯2), 3.631(5)(02¯1), 3.241(5)(022), 3.145(5)(200) and 3.006(5)(210). Chemical analysis by electron microprobe yielded MgO 0.20, FeO 0.10, NiO 5.79, CoO 1.80, CuO 29.53, ZnO 0.66, Al2O3 0.14, P2O5 0.11, As2O5 45.01, H2O 17.71 (calc.), fora total of 101.05 wt.%. The resulting empirical formula, calculated by stoichiometry (9H2O + 2OH), obtained from the crystal structure, is (Ni0.79Co0.25)Σ1.04(Cu3.78Zn0.08Mg0.05Al0.03Fe0.01)Σ3.95 (AsO4)1.98(PO4)0.02(AsO3OH)2.00(H2O)9.00. The ideal endmember formula, NiCu4(AsO4)2(AsO3OH)2(H2O)900, requires NiO 7.23, CuO 30.81, As2O5 44.51, H2O 17.45, total 100.00 wt.%. The crystal structure of hloušekite was solved by charge flipping from single-crystal XRD data and refined to R1 = 0.0599 for 1441 reflections with [Iobs > 3σ(I)]. Hlousekite is a new member of the lindackerite group (also including lindackerite, pradetite and veselovskýite) of the lindackerite supergroup. The ondrušite group of the lindackerite supergroup includes ondrušite, chudobaite, geigerite and klajite. The establishment of these two groups reflects the difference between the crystal structures of their members, mainly in the coordination environment of the Me cations. © 2014 The Mineralogical Society. Source

Plasil J.,ASCR Institute of Physics Prague | Veselovsky F.,Czech Geological Survey | Hlousek J.,U Rohacovych kasaren 24 | Skoda R.,Masaryk University | And 5 more authors.
American Mineralogist | Year: 2014

Mathesiusite, K5(UO2)4(SO4) 4(VO5)(H2O)4, a new uranyl vanadate-sulfate mineral from Jáchymov, Western Bohemia, Czech Republic, occurs on fractures of gangue associated with adolfpateraite, schoepite, čejkaite, zippeite, gypsum, and a new unnamed K-UO2-SO 4 mineral. It is a secondary mineral formed during post-mining processes. Mathesiusite is tetragonal, space group P4/n, with the unit-cell dimensions a = 14.9704(10), c = 6.8170(5) Å, V = 1527.78(18) Å3, and Z = 2. Acicular aggregates of mathesiusite consist of prismatic crystals up to ∼200 μm long and several micrometers thick. It is yellowish green with a greenish white streak and vitreous luster. The Mohs hardness is ∼2. Mathesiusite is brittle with an uneven fracture and perfect cleavage on {110} and weaker on {001}. The calculated density based on the empirical formula is 4.02 g/cm3. Mathesiusite is colorless in fragments, uniaxial (-), with ω = 1.634(3) and ε = 1.597(3). Electron microprobe analyses (average of 7) provided: K2O 12.42, SO 3 18.04, V2O5 4.30, UO3 61.46, H2O 3.90 (structure), total 100.12 (all in wt%). The empirical formula (based on 33 O atoms pfu) is: K4.87(U0.99O 2)4(S1.04O4)4(V 0.87O5)(H2O)4. The eight strongest powder X-ray diffraction lines are [dobs in Å (hkl) I rel]: 10.64 (110) 76, 7.486 (200) 9, 6.856 (001) 100, 6.237 (101) 85, 4.742 (310) 37, 3.749 (400) 27, 3.296 (401) 9, and 2.9409 (510) 17. The crystal structure of mathesiusite was solved from single-crystal X-ray diffraction data and refined to R1 = 0.0520 for 795 reflections with I > 3σ(I). It contains topologically unique heteropolyhedral sheets based on [(UO2)4(SO4)4(VO5)] 5-clusters. These clusters arise from linkages between corner-sharing quartets of uranyl pentagonal bipyramids, which define a square-shaped void at the center that is occupied by V5+ cations. Each pair of uranyl pentagonal bipyramids shares two vertices of SO4 tetrahedra. Each SO4 shares a third vertex with another cluster to form the sheets. The K+ cations are located between the sheets, together with a single H2O group. The corrugated sheets are stacked perpendicular to c. These heteropolyhedral sheets are similar to those in the structures of synthetic uranyl chromates. Raman spectral data are presented confirming the presence of UO2 2+, SO4, and molecular H 2O. Source

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