ALBERT

Description: The new minerals bobcookite (IMA 2014-030), NaAl(UO 2 ) 2 (SO 4 ) 4 ·18H 2 O and wetherillite (IMA 2014-044), Na 2 Mg(UO 2 ) 2 (SO 4 ) 4 ·18H 2 O, were found in the Blue Lizard mine, San Juan County, Utah, USA, where they occur together as secondary alteration phases in association with boyleite, chalcanthite, dietrichite, gypsum, hexahydrite, johannite, pickeringite and rozenite. Bobcookite descriptive details: lime green to greenish-yellow massive veins and columnar crystals; transparent; vitreous lustre; bright greenish-white fluorescence; pale greenish yellow streak; hardness (Mohs) 21/2; brittle; conchoidal fracture; no cleavage; moderately hygroscopic; easily soluble in cold H 2 O; density calc = 2.669 g cm –3 . Optically, biaxial (–), α = 1.501(1), β = 1.523(1), = 1.536(1) (white light); 2V meas. = 78(1)°; 2V calc. = 74°; dispersion r 〈 v , moderate. Pleochroism: X colourless, Y very pale yellow-green, Z pale yellow-green; X 〈 Y 〈 Z . EDS analyses yielded the empirical formula Na 0.97 Al 1.09 (U 1.02 O 2 ) 2 (S 0.98 O 4 ) 4 (H 2 O) 18 . Bobcookite is triclinic, P 1I, a = 7.7912(2), b = 10.5491(3), c = 11.2451(8) Å, α = 68.961(5), β = 70.909(5), = 87.139(6)°, V = 812.79(8) Å 3 and Z = 1. The structure ( R 1 = 1.65% for 3580 F o 〉 4 F ) contains [(UO 2 )(SO 4 ) 2 (H 2 O)] chains linked by NaO 4 (H 2 O) 2 octahedra to form layers. Hydrogen bonds to insular Al(H 2 O) 6 octahedra and isolated H 2 O groups hold the structure together. The mineral is named for Dr Robert (Bob) B. Cook of Auburn University, Alabama, USA. Wetherillite descriptive details: pale greenish-yellow blades; transparent; vitreous lustre; white streak; hardness (Mohs) 2; brittle; two cleavages, {101I} perfect and {010} fair; conchoidal or curved fracture; easily soluble in cold H 2 O; density calc = 2.626 g cm –3 . Optically, biaxial (+), α = 1.498(1), β = 1.508(1), = 1.519(1) (white light); 2V meas. = 88(1)°, 2V calc. = 87.9°; dispersion is r 〈 v , distinct; optical orientation: Z = b, X ^ a = 54° in obtuse β; pleochroism: X colourless, Y pale yellow-green, Z pale yellow-green; X 〈 Y Z . EDS analyses yielded the empirical formula Na 1.98 (Mg 0.58 Zn 0.24 Cu 0.11 $${\mathrm{Fe}}_{0.09}^{2+}$$ ) 1.02 (U 1.04 O 2 ) 2 (S 0.98 O 4 ) 4 (H 2 O) 18 . Wetherillite is monoclinic, P 2 1 / c, a = 20.367(1), b = 6.8329(1), c = 12.903(3) Å, β = 107.879(10)°, V = 1709.0(5) Å 3 and Z = 2. The structure ( R 1 = 1.39% for 3625 F o 〉 4 F ) contains [(UO 2 )(SO 4 ) 2 (H 2 O)] sheets parallel to {100}. Edge-sharing chains of Na(H 2 O) 5 O polyhedra link adjacent uranyl sulfate sheets forming a weakly bonded three-layer sandwich. The sandwich layers are linked to one another by hydrogen bonds through insular Mg(H 2 O) 6 octahedra and isolated H 2 O groups. The mineral is named for John Wetherill (1866–1944) and George W. Wetherill (1925–2006).

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: Calcium silicate hydrate (C-S-H) alteration was studied with flow-through experiments at 25°C and pH 9.2. Three materials with apparent Ca/Si ratios (C/S ratios) of 1.47, 1.38 and 0.86 were investigated. Physical (thermogravimetric analyses/differential thermal analysis), mineralogical (X-ray diffraction) and chemical (electron probe microanalysis, transmission electron microscopy/energy dispersive X-ray spectrometry) analyses were performed to characterize the reacting minerals. Initial stoichiometric C/S ratios were 1.22, 1.22 and 0.85, respectively. The excess of Ca is attributed mainly to the presence of calcium hydroxide intimately mixed in with C-S-H particles. The C-S-H chemical compositions were monitored during flow-through experiments in order to determine the mineral stoichiometry needed for reaction kinetics. Under our experimental conditions the stoichiometric C/S ratios decreased continuously with time. A close to stoichiometric dissolution was observed after 2 days of experiments. Using an integrated approach, the kinetics was found to be a function of the C/S. A decrease in layer-to-layer distance in the early stage of the alteration process is interpreted as interlayer Ca/Na exchange (Na being part of the pH buffering solution). A second dissolution step, marked by a close to stoichiometric release of Ca and Si, undoubtedly results from layer dissolution. The structural similarity of C-S-H and tobermorite was confirmed.

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〉