ALBERT

Description: 〈div data-abstract-type="normal"〉〈p〉Pampaloite, AuSbTe, is a new mineral discovered in the Pampalo gold mine, 65 km east of Joensuu, Finland. It forms anhedral grains (up to ~20 μm) intergrown with gold, frohbergite and altaite. Pampaloite is brittle and has a metallic lustre. Values of VHN〈span〉25〈/span〉 lie between 245 and 295 kg/mm〈span〉2〈/span〉, with a mean value of 276 kg/mm〈span〉2〈/span〉, corresponding to a Mohs hardness of ~4–5 (measured on synthetic material). In plane-polarised light, pampaloite is white with medium to strong bireflectance, weak reflectance pleochroism from slightly pinkish brown to slightly bluish white (only visible in grains of synthetic material containing multiple orientations), and strong anisotropy, with blue to light brown rotation tints; it exhibits no internal reflections. Reflectance values of pampaloite in air (〈span〉R〈/span〉〈span〉1,〈/span〉〈span〉R〈/span〉〈span〉2〈/span〉 in %) are: 60.0, 62.5 at 470 nm, 62.5, 64.8 at 546 nm, 63.2, 65.6 at 589 nm and 63.7, 66.0 at 650 nm. Ten electron-microprobe analyses of natural pampaloite give an average composition: Au 44.13, Sb 27.44 and Te 28.74, total 100.31 wt.%, corresponding to the empirical formula Au〈span〉1.00〈/span〉Sb〈span〉1.00〈/span〉Te〈span〉1.00〈/span〉 based on 3 atoms; the average of eleven analyses on synthetic pampaloite is: Au 44.03, Sb 27.26, and Te 29.08, total 100.38 wt.%, corresponding to Au〈span〉0.99〈/span〉Sb〈span〉1.00〈/span〉Te〈span〉1.01〈/span〉. The density, calculated on the basis of the empirical formula, is 9.33 g/cm〈span〉3〈/span〉.The mineral is monoclinic, space group 〈span〉C〈/span〉2/〈span〉c〈/span〉, with 〈span〉a〈/span〉 = 11.947(3), 〈span〉b〈/span〉 = 4.481(1) Å, 〈span〉c〈/span〉 = 12.335(3) Å, β = 105.83(2)°, 〈span〉V〈/span〉 = 635.3(3) Å〈span〉3〈/span〉 and 〈span〉Z〈/span〉 = 8. The crystal structure was solved and refined from the single-crystal X-ray-diffraction data of synthetic AuSbTe. The pampaloite crystal structure can be considered as a monoclinic derivative of the CdI〈span〉2〈/span〉 structure composed of [AuTe〈span〉3〈/span〉Sb〈span〉3〈/span〉] octahedra. The strongest lines in the powder X-ray diffraction pattern of synthetic pampaloite [〈span〉d〈/span〉 in Å (〈span〉I〈/span〉) (〈span〉hkl〈/span〉)] are: 4.846(24)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190709073523038-0660:S0026461X18001299:S0026461X18001299_inline1.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉02), 3.825(18)(111), 2.978(100)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190709073523038-0660:S0026461X18001299:S0026461X18001299_inline2.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉11), 2.968(50)(004), 2.242(25)(020), 2.144(55)(313), 2.063(33)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190709073523038-0660:S0026461X18001299:S0026461X18001299_inline3.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉15) and 1.789(18)(024).〈/p〉〈/div〉

Description: 〈div data-abstract-type="normal"〉〈p〉Magnesioleydetite (IMA2017-063), Mg(UO〈span〉2〈/span〉)(SO〈span〉4〈/span〉)〈span〉2〈/span〉·11H〈span〉2〈/span〉O, and straβmannite (IMA2017-086), Al(UO〈span〉2〈/span〉)(SO〈span〉4〈/span〉)〈span〉2〈/span〉F·16H〈span〉2〈/span〉O, are two new minerals from mines in Red Canyon, San Juan County, Utah, USA. Magnesioleydetite occurs in the Markey mine and straβmannite occurs in both the Markey and Green Lizard mines. Both minerals are secondary phases found in efflorescent crusts on the surfaces of mine walls. Magnesioleydetite occurs in irregular aggregates (to ~0.5 mm) of blades (to ~0.2 mm) exhibiting the following properties: transparent to translucent; pale green–yellow colour; vitreous lustre; white streak; non-fluorescent; brittle; Mohs hardness ≈ 2; irregular fracture; one perfect cleavage on {001}; and calculated density = 2.463 g/cm〈span〉3〈/span〉. Straβmannite occurs in irregular aggregates (to ~0.5 mm) of equant crystals (to ~0.2 mm) exhibiting the following properties: transparent; light yellow–green colour; vitreous to greasy lustre; nearly white streak; bright greenish-blue fluorescence; somewhat brittle, Mohs hardness ≈ 1½; irregular fracture; one good cleavage on {001}; measured and calculated densities of 2.20(2) and 2.173 g/cm〈span〉3〈/span〉, respectively; optically biaxial (–); α = 1.477(2), β = 1.485(2) and γ = 1.489(2) (white light); 2V〈span〉meas.〈/span〉 = 72(2)°; dispersion 〈span〉r〈/span〉 〉 〈span〉v〈/span〉 (slight); orientation 〈span〉Y〈/span〉 = 〈span〉b〈/span〉, 〈span〉X〈/span〉 ∧ 〈span〉c〈/span〉 = 20° (in obtuse β); pleochroism with 〈span〉X〈/span〉 = nearly colourless, 〈span〉Y〈/span〉 = pale green–yellow and 〈span〉Z〈/span〉 = light green–yellow (〈span〉X〈/span〉 Y Z). The empirical formulas for magnesioleydetite and straβmannite are (Mg〈span〉0.56〈/span〉Fe〈span〉0.26〈/span〉Zn〈span〉0.11〈/span〉Mn〈span〉0.01〈/span〉)〈span〉Σ0.94〈/span〉(U〈span〉0.99〈/span〉O〈span〉2〈/span〉)(S〈span〉1.015〈/span〉O〈span〉4〈/span〉)〈span〉2〈/span〉·11H〈span〉2〈/span〉O and Al〈span〉1.00〈/span〉Na〈span〉0.16〈/span〉(U〈span〉0.99〈/span〉O〈span〉2〈/span〉)(S〈span〉1.00〈/span〉O〈span〉4〈/span〉)〈span〉2〈/span〉[F〈span〉0.58〈/span〉(OH)〈span〉0.42〈/span〉]·16H〈span〉2〈/span〉O, respectively. Magnesioleydetite is monoclinic, 〈span〉C〈/span〉2/〈span〉c〈/span〉, 〈span〉a〈/span〉 = 11.3513(3), 〈span〉b〈/span〉 = 7.7310(2), 〈span〉c〈/span〉 = 21.7957(15) Å, β = 102.387(7)°, 〈span〉V〈/span〉 = 1868.19(16) Å〈span〉3〈/span〉 and 〈span〉Z〈/span〉 = 4. Straβmannite is monoclinic, 〈span〉C〈/span〉2/〈span〉c〈/span〉, 〈span〉a〈/span〉 = 11.0187(5), 〈span〉b〈/span〉 = 8.3284(3), 〈span〉c〈/span〉 = 26.6727(19) Å, β = 97.426(7)°, 〈span〉V〈/span〉 = 2427.2(2) and 〈span〉Z〈/span〉 = 4. The structures of magnesioleydetite (〈span〉R〈/span〉〈span〉1〈/span〉 = 0.016 for 2040 〈span〉I〈/span〉 〉 2σ〈span〉I〈/span〉 reflections) and straβmannite (〈span〉R〈/span〉〈span〉1〈/span〉 = 0.0343 for 2220 〈span〉I〈/span〉 〉 2σ〈span〉I〈/span〉 reflections) each contain uranyl-sulfate sheets based on the protasite-anion topology.〈/p〉〈/div〉

Description: 〈div data-abstract-type="normal"〉〈p〉The new mineral ammoniomathesiusite (NH〈span〉4〈/span〉)〈span〉5〈/span〉(UO〈span〉2〈/span〉)〈span〉4〈/span〉(SO〈span〉4〈/span〉)〈span〉4〈/span〉(VO〈span〉5〈/span〉)·4H〈span〉2〈/span〉O, was found in the Burro mine, San Miguel County, Utah, USA, where it occurs as a secondary phase on asphaltum/quartz matrix in association with ammoniozippeite, gypsum, jarosite and natrozippeite. The mineral forms pale yellow to greenish-yellow prisms, up to ~0.3 mm long, with pale-yellow streak and bright yellow–green fluorescence. Crystals are transparent and have vitreous lustre. The mineral is brittle, with Mohs hardness of 2½, stepped fracture and two cleavages: excellent on {110} and good on {001}. The calculated density is 3.672 g/cm〈span〉3〈/span〉. Ammoniomathesiusite is optically uniaxial (–) with ω = 1.653(2) and ε = 1.609(2) (white light). Pleochroism is: 〈span〉O〈/span〉 = green-yellow, 〈span〉E〈/span〉 = colourless; 〈span〉O〈/span〉 〉 〈span〉E〈/span〉. Electron microprobe analyses yielded the empirical formula [(NH〈span〉4〈/span〉)〈span〉4.75〈/span〉(UO〈span〉2〈/span〉)〈span〉4〈/span〉(SO〈span〉4〈/span〉)〈span〉4〈/span〉(VO〈span〉5〈/span〉)·4(H〈span〉2.07〈/span〉O). The five strongest powder X-ray diffraction lines are [〈span〉d〈/span〉〈span〉obs〈/span〉 Å(〈span〉I〈/span〉)(〈span〉hkl〈/span〉)]: 10.57(46)(110), 7.10(62)(001), 6.41(100)(101), 3.340(35)(240) and 3.226(44)(141). Ammoniomathesiusite is tetragonal, 〈span〉P〈/span〉4/〈span〉n〈/span〉 with 〈span〉a〈/span〉 = 14.9405(9), 〈span〉c〈/span〉 = 7.1020(5) Å, 〈span〉V〈/span〉 = 1585.3(2) Å〈span〉3〈/span〉 and 〈span〉Z〈/span〉 = 2. The structure of ammoniomathesiusite (〈span〉R〈/span〉〈span〉1〈/span〉 = 0.0218 for 3427 〈span〉I〈/span〉 〉 2σ〈span〉I〈/span〉) contains heteropolyhedral sheets based on [(UO〈span〉2〈/span〉)〈span〉4〈/span〉(SO〈span〉4〈/span〉)〈span〉4〈/span〉(VO〈span〉5〈/span〉)]〈span〉5–〈/span〉 clusters. The structure is identical to that of mathesiusite, with 〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190313104343836-0311:S0026461X18001123:S0026461X18001123_inline1.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉 in place of K〈span〉+〈/span〉.〈/p〉〈/div〉

Description: Litochlebite, Ag2PbBi4Se8, is a new selenide mineral from the Zalesi uranium deposit, Rychlebske hory Mountains, northern Moravia, Czech Republic. It occurs as irregular grains up to 200 {micro}m, which form aggregates up to 1-2 mm in size in a quartz gangue. These aggregates are replaced along the margins and fractures by a heterogeneous supergene Bi-Se-O phase. Other associated minerals included uraninite, hematite, and uranophane. Litochlebite is opaque, dark grey to black, has a dark grey streak and a metallic luster. No cleavage was observed; the mineral is brittle with an irregular fracture. The VHN10g microhardness 230 (227-234) kg/mm2 corresponds to a Mohs hardness of about 3; the calculated density is 7.90 g/cm3. In reflected light, litochlebite is white, with weak bireflectance (only in oil) and pleochroism from white with a very faint yellowish tint to white with a very faint bluish tint. Between crossed polars, the anisotropy is moderate both in air and in oil, with dark grey to brown polarization-colors. Reflectance values in air (Rmin, Rmax in %, {lambda} nm) are: 44.5-49.9 (470), 45.1-50.5 (546), 45.6-51.3 (589), 45.4-51.8 (650). Litochlebite is monoclinic, space group P21/m, with a 13.182(2), b 4.1840(8), c 15.299(2) A, {beta} 109.11(1){degrees}, V 797.3(2) A3, and a:b:c 3.1506:1:3.6565. The main lines of the X-ray powder-diffraction pattern [d in A(I)(hkl)] are: 3.684(53) (301), 3.201(76)(104), 3.028(100)(31[IMG]f2.gif" ALT="Formula" BORDER="0"〉), 2.980(88)(31[IMG]f3.gif" ALT="Formula" BORDER="0"〉) and 2.892(95)(005). Its average composition (electron-microprobe data) is Cu 0.10, Ag 10.27, Cd 0.05, Pb 11.73, Bi 43.27, Se 32.93, S 0.01, total 98.36 wt.%. The resulting empirical formula, written on the basis 15 apfu, is (Ag1.84Cu0.03){sum}1.87 (Pb1.09Cd0.01){sum}1.10Bi3.99Se8.04. The ideal formula, Ag2PbBi4Se8, requires Ag 11.41, Pb 10.96, Bi 44.22, Se 33.41, total 100.00 wt.%. The crystal structure of litochlebite has been solved by direct methods and refined to R1 = 3.89% on the basis of 938 unique reflections [Fo 〉 4{sigma}(Fo)] collected on a Bruker AXS diffractometer with a CCD detector and MoK{alpha} radiation. The crystal structure contains one lead site, four independent Bi sites, four silver sites and eight independent Se sites. One Ag site is an octahedrally coordinated (2 + 4) site in the pseudotetragonal layer, the other Ag site has a distorted tetrahedral coordination. The remaining Ag sites have low occupancies. Litochlebite is an Ag-dominant isotype of watkinsonite, Cu2PbBi4Se8, and structurally related to berryite, Cu3Ag2Pb3Bi7S16.

Description: Sejkoraite-(Y), the triclinic (Y1.98Dy0.24){sum}2.22H0.34+ [(UO2)8O88O7OH(SO4)4](OH)(H2O)26, is a new member of the zippeite group from the [C]ervena vein, Jachymov (Street Joachimsthal) ore district, Western Bohemia, Czech Republic. It grows on altered surface of relics of primary minerals: uraninite, chalcopyrite, and tennantite, and is associated with pseudojohannite, rabejacite, uranopilite, zippeite, and gypsum. Sejkoraite-(Y) forms crystalline aggregates consisting of yellow-orange to orange crystals, rarely up to 1 mm in diameter. The crystals have a strong vitreous luster and a pale yellow-to-yellow streak. The crystals are very brittle with perfect {100} cleavage and uneven fracture. The Mohs hardness is about 2. The mineral is not fluorescent either in short- or long-wavelength UV radiation. Sejkoraite-(Y) is yellow, with no visible pleochroism, biaxial negative with {alpha}' = 1.62(2), {beta}' = 1.662(3), {gamma}' = 1.73(1), 2Vcalc = 79{degrees}. The empirical chemical formula (mean of 8 electron microprobe point analyses) was calculated on the basis of 12 (S + U) atoms: (Y1.49Dy0.17Gd0.11Er0.07Yb0.05Sm0.02){sum}1.90H0.54 + [(UO2)8.19O7OH(SO4)3.81](H2O)26.00. Sejkoraite-(Y) is triclinic, space group P[IMG]f1.gif" ALT="Formula" BORDER="0"〉, a = 14.0743(6), b = 17.4174(7), c = 17.7062(8) A, {alpha} = 75.933(4), {beta} = 128.001(5), {gamma} = 74.419(4){degrees}, V = 2777.00(19) A3, Z = 2, Dcalc = 4.04 g/cm3. The seven strongest reflections in the X-ray powder diffraction pattern are [dobs in A (I) (hkl)]: 9.28 (100) (100), 4.64 (39) (200), 3.631 (6) ([IMG]f1.gif" ALT="Formula" BORDER="0"〉42), 3.451 (13) ([IMG]f1.gif" ALT="Formula" BORDER="0"〉44), 3.385 (10) ([IMG]f2.gif" ALT="Formula" BORDER="0"〉[IMG]f3.gif" ALT="Formula" BORDER="0"〉2), 3.292 (9) (044), 3.904(7) (300), 2.984 (10) ([IMG]f1.gif" ALT="Formula" BORDER="0"〉[IMG]f3.gif" ALT="Formula" BORDER="0"〉2). The crystal structure of sejkoraite-(Y) has been solved by the charge flipping method from single-crystal X-ray diffraction data and refined to Robs = 0.060 with GOFobs = 2.38, based on 6511 observed reflections. The crystal structure consists of uranyl sulfate sheets of zippeite anion topology, which alternate with an interlayer containing Y3+(H2O)n polyhedra and uncoordinated H2O groups. Two yttrium atoms are linked to the sheet directly via uranyl oxygen atom, and the remaining one is bonded by hydrogen bonds only. In the Raman and infrared spectrum of sejkoraite-(Y) there are dominating stretching vibrations of SO4 tetrahedra (~1200-1100 cm-1), UO22+ stretching vibrations (~900-800 cm-1), and O-H stretching (~3500-3200 cm-1) and H-O-H bending modes (~1640 cm-1). The new mineral is named to honor Ji[r]i Sejkora, a Czech mineralogist of the National Museum in Prague.

Description: The crystal structure of natural zippeite, K1.85H+0.15[(UO2)4O2(SO4)2OH2](H2O)4, from Jachymov, Czech Republic, has been determined by single-crystal X-ray diffraction and refined to R1 = 0.0367. Zippeite is monoclinic, space group C2/m, with a 8.7802(6), b 13.9903(12), c 8.8630(6) A, {beta} 104.524(7){degrees}, V 1053.92(12) A3 and Z = 2. The structure consists of structural sheets of the zippeite uranyl anion topology and an interlayer, in which split K+ atoms and disordered O atoms (of the H2O groups) are located. The structure unit [(UO2)4O2(SO4)2OH2]2- is novel for both natural and synthetic compounds, but generally consistent with the known zippeite-type structures. The structural formula is in agreement with bond-valence analysis and the results of an electron-microprobe study. The composition of the zippeite specimen studied is assessed from the point of view of the bond-valence approach. Further, we comment on morphology of zippeite, its optical properties, and its relationship to the crystal structure.

Description: 〈div data-abstract-type="normal"〉〈p〉The new mineral feynmanite, Na(UO〈span〉2〈/span〉)(SO〈span〉4〈/span〉)(OH)·3.5H〈span〉2〈/span〉O, was found in both the Blue Lizard and Markey mines, San Juan County, Utah, USA, where it occurs as a secondary phase on pyrite-rich asphaltum in association with chinleite-(Y), gypsum, goethite, natrojarosite, natrozippeite, plášilite, shumwayite (Blue Lizard) and wetherillite (Markey). The mineral is pale greenish yellow with a white streak and fluoresces bright greenish white under a 405 nm laser. Crystals are transparent with a vitreous lustre. It is brittle, with a Mohs hardness of ~2, irregular fracture and one perfect cleavage on {010}. The calculated density is 3.324 g cm〈span〉–3〈/span〉. Crystals are thin needles or blades, flattened on {010} and elongate on [100], exhibiting the forms {010}, {001}, {101} and {10〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190522072108342-0385:S0026461X18001172:S0026461X18001172_inline1.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉}, and are up to ~0.1 mm in length. Feynmanite is optically biaxial (–), with α = 1.534(2), β = 1.561(2) and γ = 1.571(2) (white light); 2V〈span〉meas.〈/span〉 = 62(2)°; no dispersion; and optical orientation: 〈span〉X〈/span〉 = 〈span〉b〈/span〉, 〈span〉Y〈/span〉 ≈ 〈span〉a,〈/span〉〈span〉Z〈/span〉 ≈ 〈span〉c〈/span〉. It is weakly pleochroic: 〈span〉X〈/span〉 = colourless, 〈span〉Y〈/span〉 = very pale green yellow and 〈span〉Z〈/span〉 = pale green yellow (〈span〉X〈/span〉 Y Z). Electron microprobe analyses (WDS mode) provided (Na〈span〉0.84〈/span〉Fe〈span〉0.01〈/span〉)(U〈span〉1.01〈/span〉O〈span〉2〈/span〉)(S〈span〉1.01〈/span〉O〈span〉4〈/span〉)(OH)·3.5H〈span〉2〈/span〉O. The five strongest powder X-ray diffraction lines are [〈span〉d〈/span〉〈span〉obs〈/span〉 Å(〈span〉I〈/span〉)(〈span〉hkl〈/span〉)]: 8.37(100)(010), 6.37(33)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190522072108342-0385:S0026461X18001172:S0026461X18001172_inline2.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉01,101), 5.07(27)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190522072108342-0385:S0026461X18001172:S0026461X18001172_inline3.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉11,111), 4.053(46)(004,021) and 3.578(34)(120). Feynmanite is monoclinic, has space group 〈span〉P〈/span〉2/〈span〉n〈/span〉, 〈span〉a〈/span〉 = 6.927(3), 〈span〉b〈/span〉 = 8.355(4), 〈span〉c〈/span〉 = 16.210(7) Å, β = 90.543(4)°, 〈span〉V〈/span〉 = 938.1(7) Å〈span〉3〈/span〉 and 〈span〉Z〈/span〉 = 4. The structure of feynmanite (〈span〉R〈/span〉〈span〉1〈/span〉 = 0.0371 for 1879 〈span〉I〈/span〉〈span〉o〈/span〉 〉 2σ〈span〉I〈/span〉) contains edge-sharing pairs of pentagonal bipyramids that are linked by sharing corners with SO〈span〉4〈/span〉 groups, yielding a [(UO〈span〉2〈/span〉)〈span〉2〈/span〉(SO〈span〉4〈/span〉)〈span〉2〈/span〉(OH)〈span〉2〈/span〉]〈span〉2–〈/span〉 sheet based on the phosphuranylite anion topology. The sheet is topologically identical to those in deliensite, johannite and plášilite. The dehydration of feynmanite to plášilite results in interlayer collapse involving geometric reconfiguration of the sheets and the ordering of Na.〈/p〉〈/div〉