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Frank N Keutsch - One of the best experts on this subject based on the ideXlab platform.

  • agmantinite ag2mnsns4 a new mineral with a wurtzite derivative structure from the uchucchacua polymetallic deposit lima department peru
    Mineralogical Magazine, 2019
    Co-Authors: Frank N Keutsch, Emil Makovicky, Dan Topa, Rie T Fredrickson, Werner H. Paar
    Abstract:

    Agmantinite, ideally Ag 2 MnSnS 4 , is a new mineral from the Uchucchacua polymetallic deposit, Oyon district, Catajambo, Lima Department, Peru. It occurs as orange–red crystals up to 100 μm across. Agmantinite is translucent with adamantine lustre and possesses a red streak. It is brittle. Neither fracture nor cleavage were observed. Based on the empirical formula the calculated density is 4.574 g/cm 3 . On the basis of chemically similar compounds the Mohs hardness is estimated at between 2 to 2½. In plane-polarised light agmantinite is white with red internal reflections. It is weakly bireflectant with no observable pleochroism with red internal reflections. Between Crossed Polars, agmantinite is weakly anisotropic with reddish brown to greenish grey rotation tints. The reflectances ( R min and R max ) for the four standard wavelengths are: 19.7 and 22.0 (470 nm); 20.5 and 23.2 (546 nm); 21.7 and 2.49 (589 nm); and 20.6 and 23.6 (650 nm), respectively. Agmantinite is orthorhombic, space group P 2 1 nm , with unit-cell parameters: a = 6.632(2), b = 6.922(2), c = 8.156(2) A, V = 374.41(17) A 3 , a : b : c 0.958:1:1.178 and Z = 2. The crystal structure was refined to R = 0.0575 for 519 reflections with I > 2σ( I ). Agmantinite is the first known mineral of ${M}_{\rm 2}^{\rm I} $ M II M IV S 4 type that is derived from wurtzite rather than sphalerite by ordered substitution of Zn, analogous to the substitution pattern for deriving stannite from sphalerite. The six strongest X-ray powder-diffraction lines derived from single-crystal X-ray diffraction data [ d in A (intensity)] are: 3.51 (s), 3.32 (w), 3.11 (vs), 2.42 (w), 2.04 (m) and 1.88 (m). The empirical formula (based on 8 apfu) is (Ag 1.94 Cu 0.03 ) Σ1.97 (Mn 0.98 Zn 0.05 ) Σ1.03 Sn 0.97 S 4.03 .The crystal structure-derived formula is Ag 2 (Mn 0.69 Zn 0.31 ) Σ1.00 SnS 4 and the simplified formula is Ag 2 MnSnS 4 . The name is for the composition and the new mineral and mineral name have been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2014-083).

  • Petříčekite, CuSe2, a New Member of the Marcasite Group from the Předbořice Deposit, Central Bohemia Region, Czech Republic
    MDPI AG, 2016
    Co-Authors: Luca Bindi, Frank N Keutsch, Hans-jürgen Förster, Günter Grundmann, Chris J. Stanley
    Abstract:

    Petříčekite, ideally CuSe2, is a new mineral from the Předbořice deposit, Central Bohemia Region, Czech Republic. It occurs as rare inclusions, up to 150 μm across, in large eucairite grains closely associated with athabascaite/klockmannite and unknown selenide phases. Petříčekite is opaque with a metallic luster and shows a black streak. It is brittle; the Vickers hardness (VHN15) is 33 kg/mm2 (range: 28–40 kg/mm2) (Mohs hardness of ~2–2½). In reflected light, petříčekite is pale blue grey to pale pinkish, weakly pleochroic and weakly bireflectant from slightly blue-grey to slightly pinkish-grey. Under Crossed Polars, it is anisotropic with light grey-blue to light pink rotation tints. Internal reflections are absent. Reflectance percentages for the four COM (Commission on Ore Mineralogy) wavelengths (Rmin and Rmax) are 42.35, 41.8 (470 nm), 42.0, 42.2 (546 nm), 41.9, 42.35 (589 nm) and 42.05, 42.85 (650 nm), respectively. Petříčekite is orthorhombic, space group Pnnm, with a = 4.918(2) Å; b = 6.001(2) Å; c = 3.670(1) Å; V = 108.31(1) Å3; Z = 2. The crystal structure (R1 = 0.0336 for 159 reflections with I > 2σ(I)) belongs to the marcasite-type structure. It consists of edge-sharing chains of CuSe6 octahedra parallel to [001] linked by sharing Se2 dimers. The Se–Se bonds are all parallel to (001). The five strongest powder-diffraction lines (d in Å (I/I0) (hkl)) are: 2.938 (70) (101); 2.639 (100) (111); 2.563 (85) (120); 1.935 (70) (211); 1.834 (30) (002). The mean of nine electron-microprobe analyses on the crystal used for the structural study gave Ag 0.22(13), Cu 15.39(15), Hg 0.01(3), Pb 0.03(2), Fe 12.18(10), Pd 0.11(4), S 0.09(1), Se 71.61(29) and total 99.64(41) wt %, corresponding on the basis of a total of three atoms, to (Cu0.53Fe0.48)Σ1.01(Se1.98S0.01)Σ1.99. Additional crystals exhibiting higher Cu contents (up to 0.74 a.p.f.u.) were also investigated. The new mineral has been approved by the IMA-NMNC Commission (2015-111) and named after Václav Petříček, renowned crystallographer of the Institute of Physics of the Czech Academy of Sciences, Prague. Optical, compositional and structural properties confirm that nearly pure petříčekite also formed as late-stage mineral in the Se mineralization at El Dragón, Bolivia. It has end-member composition, Cu0.99Se2.00 (n = 5), and is typically associated with krut’aite of ideal composition, native selenium and goethite. Finally, optical and chemical data indicate that pure petříčekite is likely present also at Sierra de Cacheuta, Argentina

  • manganoquadratite agmnass3 a new manganese bearing sulfosalt from the uchucchacua polymetallic deposit lima department peru description and crystal structure
    American Mineralogist, 2012
    Co-Authors: Paola Onazzi, Frank N Keutsch, Luca Indi
    Abstract:

    Manganoquadratite, ideally AgMnAsS3, is a new mineral from the Uchucchacua polymetallic deposit, Oyon district, Catajambo, Lima Department, Peru. It occurs as dark gray, anhedral to subhedral grains up 0.5 mm across, closely associated with alabandite, Mn-rich calcite, Mn-rich sphalerite, proustite, pyrite, pyrrhotite, tennantite, argentotennantite, stannite, and other unnamed minerals of the system Pb-Ag-Sb-Mn-As-S. Manganoquadratite is opaque with a metallic luster and possesses a reddish-brown streak. It is brittle, the Vickers microhardness (VHN10) is 81 kg/mm 2 (range 75–96) (corresponding Mohs hardness of 2–2½). The calculated density is 4.680 g/cm 3 (on the basis of the empirical formula). In plane-polarized reflected light, manganoquadratite is moderately bireflectant and very weakly pleochroic from dark gray to a blue gray. Internal reflections are absent. Between Crossed Polars, the mineral is anisotropic, without characteristic rotation tints. Reflectance percentages (Rmin and Rmax) for the four standard COM wavelengths are 29.5, 31.8 (471.1 nm), 28.1, 30.5 (548.3 nm), 27.3, 29.3 (586.6 nm), and 26.0, 28.2 (652.3 nm), respectively. Manganoquadratite is tetragonal, space group P4322, with unit-cell parameters: a = 5.4496(5), c = 32.949(1) A, V = 978.5(1) A 3 , c:a = 6.046, Z = 8. The structure, refined to R1 = 0.0863 for 907 reflections with Fo > 4σ(Fo), consists of a stacking along [001] of alabandite-like Mn2S2 layers connected to each to other by a couple of AgAsS2 sheets where As 3+ forms typical AsS3 groups, whereas Ag + cations are fivefold coordinated. The six strongest lines in the observed X-ray powder-diffraction pattern [d in A (I/I0) (hkl)] are: 3.14 (60) (116), 2.739 (50) (0 0 12), 2.710 (100) (200), 1.927(70) (2 0 12 + 220), 1.645 (25) (3 0 16), and 1.573 (20) (2 2 12). Electron microprobe analyses gave the chemical formula (on the basis of six atoms) (Ag0.95Cu0.05)Σ=1.00 (Mn0.96Pb0.04)Σ=1.00(As0.87Sb0.14)Σ=1.01S2.99, leading to the simplified formula AgMnAsS3.

Werner H. Paar - One of the best experts on this subject based on the ideXlab platform.

  • agmantinite ag2mnsns4 a new mineral with a wurtzite derivative structure from the uchucchacua polymetallic deposit lima department peru
    Mineralogical Magazine, 2019
    Co-Authors: Frank N Keutsch, Emil Makovicky, Dan Topa, Rie T Fredrickson, Werner H. Paar
    Abstract:

    Agmantinite, ideally Ag 2 MnSnS 4 , is a new mineral from the Uchucchacua polymetallic deposit, Oyon district, Catajambo, Lima Department, Peru. It occurs as orange–red crystals up to 100 μm across. Agmantinite is translucent with adamantine lustre and possesses a red streak. It is brittle. Neither fracture nor cleavage were observed. Based on the empirical formula the calculated density is 4.574 g/cm 3 . On the basis of chemically similar compounds the Mohs hardness is estimated at between 2 to 2½. In plane-polarised light agmantinite is white with red internal reflections. It is weakly bireflectant with no observable pleochroism with red internal reflections. Between Crossed Polars, agmantinite is weakly anisotropic with reddish brown to greenish grey rotation tints. The reflectances ( R min and R max ) for the four standard wavelengths are: 19.7 and 22.0 (470 nm); 20.5 and 23.2 (546 nm); 21.7 and 2.49 (589 nm); and 20.6 and 23.6 (650 nm), respectively. Agmantinite is orthorhombic, space group P 2 1 nm , with unit-cell parameters: a = 6.632(2), b = 6.922(2), c = 8.156(2) A, V = 374.41(17) A 3 , a : b : c 0.958:1:1.178 and Z = 2. The crystal structure was refined to R = 0.0575 for 519 reflections with I > 2σ( I ). Agmantinite is the first known mineral of ${M}_{\rm 2}^{\rm I} $ M II M IV S 4 type that is derived from wurtzite rather than sphalerite by ordered substitution of Zn, analogous to the substitution pattern for deriving stannite from sphalerite. The six strongest X-ray powder-diffraction lines derived from single-crystal X-ray diffraction data [ d in A (intensity)] are: 3.51 (s), 3.32 (w), 3.11 (vs), 2.42 (w), 2.04 (m) and 1.88 (m). The empirical formula (based on 8 apfu) is (Ag 1.94 Cu 0.03 ) Σ1.97 (Mn 0.98 Zn 0.05 ) Σ1.03 Sn 0.97 S 4.03 .The crystal structure-derived formula is Ag 2 (Mn 0.69 Zn 0.31 ) Σ1.00 SnS 4 and the simplified formula is Ag 2 MnSnS 4 . The name is for the composition and the new mineral and mineral name have been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2014-083).

E. Bonaccorsi - One of the best experts on this subject based on the ideXlab platform.

  • Tazieffite, Pb20Cd2(As,Bi)22S50Cl10, a new chloro-sulfosalt from Mutnovsky volcano, Kamchatka Peninsula, Russian Federation
    The American Mineralogist, 2009
    Co-Authors: M. Zelenski, E. Makovicky, A. Garavelli, D. Pinto, F. Vurro, Y. Moëlo, L. Bindi, E. Bonaccorsi
    Abstract:

    Tazieffite, ideally Pb20Cd2(As,Bi)22S50Cl10, is a new mineral from the high-temperature fumaroles of the Mutnovsky volcano, Kamchatka Peninsula, Russian Federation. It occurs as tiny, slender, needle-shaped crystals, up to 400 µm long and 10 µm across, generally forming fibrous aggregates. Tazieffite is closely associated with greenockite, galena, mutnovskite, kudriavite, and Cd-rich cannizzarite. Other minerals spatially associated are pyrite, anhydrite, and cristobalite. Tazieffite is silvery-gray in color, occasionally with a magenta tint when it forms aggregates of extremely fine needles. It has a black streak and metallic luster. In plane-polarized incident light, tazieffite is weakly bireflectant and weakly pleochroic from dark gray to a blue-gray. Between Crossed Polars, the mineral is weakly anisotropic, without characteristic rotation tints. Reflectance percentages measured in air (Rmin and Rmax) for a single grain are 33.9, 34.1 (471.1 nm), 32.8, 33.0 (548.3 nm), 32.4, 32.6 (586.6 nm), and 30.9, 31.1 (652.3 nm), respectively. Electron microprobe analyses yield the following ranges of concentrations: Pb 41.88–44.14 (avg. 42.90), Cd 0.87–1.16 (avg. 1.03), Sn 0.31–0.69 (avg. 0.48), Bi 20.43–22.94 (avg. 21.90), As 8.64–10.73 (avg. 9.66), S 16.10–17.48 (avg. 16.58), Se 0.82–1.28 (avg. 1.04), Cl 2.39–2.77 (avg. 2.63), Br 0.09–0.15 (avg. 0.12), I 0.27–0.58 (avg. 0.42). The empirical chemical formula, calculated on the basis of 44 cations, is Pb20.06(Cd0.89Sn0.39In0.02)Σ1.30(As12.49Bi10.15)Σ22.64 (S50.08Se1.28)Σ51.36(Cl7.18I0.32Br0.15)Σ7.65. Tazieffite is closely related to the halogen-sulfosalt vurroite, Pb20Sn2Bi22S54Cl6, both from a chemical and structural point of view. It represents the (Cd,As)-dominant of vurroite, according to the coupled heterovalent substitution Sn4+ + 2S2– → Cd2+ + 2Cl–. The crystal structure of tazieffite was refined in the space group C2/c to R = 0.0370 for 4271 reflections with I > 2σ(I). Unit-cell parameters are a = 8.3520(17), b = 45.5920(92), c = 27.2610(55) Å, β = 98.84(3)°, with V = 10257(4) Å3, and Z = 4. The structure of tazieffite consists of lozenge-shaped composite rods made of coordination polyhedra of Pb around an octahedrally coordinated (Cd,Sn,Pb) position, interconnected into layers parallel to (010). These layers are separated by ribbons of As and Bi in distorted octahedral coordination. The ribbons form wavy, discontinuous double layers of the PbS archetype. Lone electron pairs of As and Bi are accommodated in the central portions of the PbS-like layers. The possibility that small amounts of NH4+ are incorporated in the crystal structure of tazieffite is discussed. The name of this new mineral species (IMA 2008-012) honors Haroun Tazieff (Warszawa, May 11, 1914–Paris, February 6, 1998), famous Belgian/French volcanologist, who was a pioneer in the field study of volcanoes and devoted his life to the study of volcanic gases.

Luca Indi - One of the best experts on this subject based on the ideXlab platform.

  • manganoquadratite agmnass3 a new manganese bearing sulfosalt from the uchucchacua polymetallic deposit lima department peru description and crystal structure
    American Mineralogist, 2012
    Co-Authors: Paola Onazzi, Frank N Keutsch, Luca Indi
    Abstract:

    Manganoquadratite, ideally AgMnAsS3, is a new mineral from the Uchucchacua polymetallic deposit, Oyon district, Catajambo, Lima Department, Peru. It occurs as dark gray, anhedral to subhedral grains up 0.5 mm across, closely associated with alabandite, Mn-rich calcite, Mn-rich sphalerite, proustite, pyrite, pyrrhotite, tennantite, argentotennantite, stannite, and other unnamed minerals of the system Pb-Ag-Sb-Mn-As-S. Manganoquadratite is opaque with a metallic luster and possesses a reddish-brown streak. It is brittle, the Vickers microhardness (VHN10) is 81 kg/mm 2 (range 75–96) (corresponding Mohs hardness of 2–2½). The calculated density is 4.680 g/cm 3 (on the basis of the empirical formula). In plane-polarized reflected light, manganoquadratite is moderately bireflectant and very weakly pleochroic from dark gray to a blue gray. Internal reflections are absent. Between Crossed Polars, the mineral is anisotropic, without characteristic rotation tints. Reflectance percentages (Rmin and Rmax) for the four standard COM wavelengths are 29.5, 31.8 (471.1 nm), 28.1, 30.5 (548.3 nm), 27.3, 29.3 (586.6 nm), and 26.0, 28.2 (652.3 nm), respectively. Manganoquadratite is tetragonal, space group P4322, with unit-cell parameters: a = 5.4496(5), c = 32.949(1) A, V = 978.5(1) A 3 , c:a = 6.046, Z = 8. The structure, refined to R1 = 0.0863 for 907 reflections with Fo > 4σ(Fo), consists of a stacking along [001] of alabandite-like Mn2S2 layers connected to each to other by a couple of AgAsS2 sheets where As 3+ forms typical AsS3 groups, whereas Ag + cations are fivefold coordinated. The six strongest lines in the observed X-ray powder-diffraction pattern [d in A (I/I0) (hkl)] are: 3.14 (60) (116), 2.739 (50) (0 0 12), 2.710 (100) (200), 1.927(70) (2 0 12 + 220), 1.645 (25) (3 0 16), and 1.573 (20) (2 2 12). Electron microprobe analyses gave the chemical formula (on the basis of six atoms) (Ag0.95Cu0.05)Σ=1.00 (Mn0.96Pb0.04)Σ=1.00(As0.87Sb0.14)Σ=1.01S2.99, leading to the simplified formula AgMnAsS3.

Emil Makovicky - One of the best experts on this subject based on the ideXlab platform.

  • agmantinite ag2mnsns4 a new mineral with a wurtzite derivative structure from the uchucchacua polymetallic deposit lima department peru
    Mineralogical Magazine, 2019
    Co-Authors: Frank N Keutsch, Emil Makovicky, Dan Topa, Rie T Fredrickson, Werner H. Paar
    Abstract:

    Agmantinite, ideally Ag 2 MnSnS 4 , is a new mineral from the Uchucchacua polymetallic deposit, Oyon district, Catajambo, Lima Department, Peru. It occurs as orange–red crystals up to 100 μm across. Agmantinite is translucent with adamantine lustre and possesses a red streak. It is brittle. Neither fracture nor cleavage were observed. Based on the empirical formula the calculated density is 4.574 g/cm 3 . On the basis of chemically similar compounds the Mohs hardness is estimated at between 2 to 2½. In plane-polarised light agmantinite is white with red internal reflections. It is weakly bireflectant with no observable pleochroism with red internal reflections. Between Crossed Polars, agmantinite is weakly anisotropic with reddish brown to greenish grey rotation tints. The reflectances ( R min and R max ) for the four standard wavelengths are: 19.7 and 22.0 (470 nm); 20.5 and 23.2 (546 nm); 21.7 and 2.49 (589 nm); and 20.6 and 23.6 (650 nm), respectively. Agmantinite is orthorhombic, space group P 2 1 nm , with unit-cell parameters: a = 6.632(2), b = 6.922(2), c = 8.156(2) A, V = 374.41(17) A 3 , a : b : c 0.958:1:1.178 and Z = 2. The crystal structure was refined to R = 0.0575 for 519 reflections with I > 2σ( I ). Agmantinite is the first known mineral of ${M}_{\rm 2}^{\rm I} $ M II M IV S 4 type that is derived from wurtzite rather than sphalerite by ordered substitution of Zn, analogous to the substitution pattern for deriving stannite from sphalerite. The six strongest X-ray powder-diffraction lines derived from single-crystal X-ray diffraction data [ d in A (intensity)] are: 3.51 (s), 3.32 (w), 3.11 (vs), 2.42 (w), 2.04 (m) and 1.88 (m). The empirical formula (based on 8 apfu) is (Ag 1.94 Cu 0.03 ) Σ1.97 (Mn 0.98 Zn 0.05 ) Σ1.03 Sn 0.97 S 4.03 .The crystal structure-derived formula is Ag 2 (Mn 0.69 Zn 0.31 ) Σ1.00 SnS 4 and the simplified formula is Ag 2 MnSnS 4 . The name is for the composition and the new mineral and mineral name have been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2014-083).

  • Tsygankoite, Mn8Tl8Hg2(Sb21Pb2Tl)Σ24S48, a New Sulfosalt from the Vorontsovskoe Gold Deposit, Northern Urals, Russia
    Minerals, 2018
    Co-Authors: Anatoly V. Kasatkin, Emil Makovicky, Atali A. Agakhanov, Vladimir Yu. Karpenko, Radek Škoda, Fabrizio Nestola
    Abstract:

    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 associated minerals also include aktashite, alabandite, arsenopyrite, barite, cinnabar, fluorapatite, orpiment, pyrite, realgar, routhierite, sphalerite, tilasite, and titanite. The new mineral is non-fluorescent, black, and 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 kg/mm2) and its calculated density is 5.450 g cm. 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, Hg 5.42, Tl 26.05, Pb 5.84, As 3.39, Sb 30.89, S 21.87, total 99.75. The empirical formula, calculated on the basis of 90 atoms pfu, is: Mn8.06Tl8.00Hg1.90(Sb17.87As3.19Pb1.99Tl0.97)Σ24.02S48.03. Tsygankoite is monoclinic, space group C2/m, a = 21.362(4) A, b = 3.8579(10) A, c = 27.135(4) A, β = 106.944(14)°, V = 2139.19(17) A3 and Z = 1. The five strongest diffraction peaks from X-ray powder pattern (listed as (d,A(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 the second on SnS-archetype. Tsygankoite has been approved by the IMA-CNMNC under the number 2017-088. It is named for Mikhail V. Tsyganko, a mineral collector from Severouralsk, Northern Urals, Russia, who collected the samples where the new mineral was discovered.