Magnesioleydetite and straβmannite, two new uranyl sulfate minerals with sheet structures from Red Canyon, Utah

2018 ◽  
Vol 83 (03) ◽  
pp. 349-360 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Anatoly V. Kasatkin ◽  
Barbara P. Nash ◽  
Joe Marty

AbstractMagnesioleydetite (IMA2017-063), Mg(UO2)(SO4)2·11H2O, and straβmannite (IMA2017-086), Al(UO2)(SO4)2F·16H2O, 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/cm3. 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/cm3, respectively; optically biaxial (–); α = 1.477(2), β = 1.485(2) and γ = 1.489(2) (white light); 2Vmeas.= 72(2)°; dispersionr>v(slight); orientationY=b,X∧c= 20° (in obtuse β); pleochroism withX= nearly colourless,Y= pale green–yellow andZ= light green–yellow (X<Y<Z). The empirical formulas for magnesioleydetite and straβmannite are (Mg0.56Fe0.26Zn0.11Mn0.01)Σ0.94(U0.99O2)(S1.015O4)2·11H2O and Al1.00Na0.16(U0.99O2)(S1.00O4)2[F0.58(OH)0.42]·16H2O, respectively. Magnesioleydetite is monoclinic,C2/c,a= 11.3513(3),b= 7.7310(2),c= 21.7957(15) Å, β = 102.387(7)°,V= 1868.19(16) Å3andZ= 4. Straβmannite is monoclinic,C2/c,a= 11.0187(5),b= 8.3284(3),c= 26.6727(19) Å, β = 97.426(7)°,V= 2427.2(2) andZ= 4. The structures of magnesioleydetite (R1= 0.016 for 2040I> 2σIreflections) and straβmannite (R1= 0.0343 for 2220I> 2σIreflections) each contain uranyl-sulfate sheets based on the protasite-anion topology.

2020 ◽  
Vol 84 (5) ◽  
pp. 753-765 ◽  
Author(s):  
Anthony R. Kampf ◽  
Travis A. Olds ◽  
Jakub Plášil ◽  
Peter C. Burns ◽  
Joe Marty

AbstractThe new minerals natromarkeyite, Na2Ca8(UO2)4(CO3)13(H2O)24⋅3H2O (IMA2018-152) and pseudomarkeyite, Ca8(UO2)4(CO3)12(H2O)18⋅3H2O (IMA2018-114) were found in the Markey mine, San Juan County, Utah, USA, where they occur as secondary phases on asphaltum. Natromarkeyite properties are: untwinned blades and tablets to 0.2 mm, pale yellow green colour; transparent; white streak; bright bluish white fluorescence (405 nm laser); vitreous to pearly lustre; brittle; Mohs hardness 1½ to 2; irregular fracture; three cleavages ({001} perfect, {100} and {010} good); density = 2.70(2) g cm–3; biaxial (–) with α = 1.528(2), β = 1.532(2) and γ = 1.533(2); and pleochroism is X = pale green yellow, Y ≈ Z = light green yellow. Pseudomarkeyite properties are: twinned tapering blades and tablets to 1 mm; pale green yellow colour; transparent; white streak; bright bluish white fluorescence (405 nm laser); vitreous to pearly lustre; brittle; Mohs hardness ≈ 1; stepped fracture; three cleavages ({10$\bar{1}$} very easy, {010} good, {100} fair); density = 2.88(2) g cm–3; biaxial (–) with α = 1.549(2), β = 1.553(2) and γ = 1.557(2); and it is nonpleochroic. The Raman spectra of markeyite, natromarkeyite and pseudomarkeyite are very similar and exhibit bands consistent with UO22+, CO32– and O–H. Electron microprobe analyses provided the empirical formula Na2.01Ca7.97Mg0.03Cu2+0.05(UO2)4(CO3)13(H2O)24⋅3H2O (–0.11 H) for natromarkeyite and Ca7.95(UO2)4(CO3)12(H2O)18⋅3H2O (+0.10 H) for pseudomarkeyite. Natromarkeyite is orthorhombic, Pmmn, a = 17.8820(13), b = 18.3030(4), c = 10.2249(3) Å, V = 3336.6(3) Å3 and Z = 2. Pseudomarkeyite is monoclinic, P21/m, a = 17.531(3), b = 18.555(3), c = 9.130(3) Å, β = 103.95(3)°, V = 2882.3(13) Å3 and Z = 2. The structures of natromarkeyite (R1 = 0.0202 for 2898 I > 2σI) and pseudomarkeyite (R1 = 0.0787 for 2106 I > 2σI) contain uranyl tricarbonate clusters that are linked by (Ca/Na)–O polyhedra forming thick corrugated heteropolyhedral layers. Natromarkeyite is isostructural with markeyite; pseudomarkeyite has a very similar structure.


2019 ◽  
Vol 84 (1) ◽  
pp. 131-141 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Barbara P. Nash ◽  
Ivan Němec ◽  
Joe Marty

AbstractUroxite (IMA2018-100), [(UO2)2(C2O4)(OH)2(H2O)2]⋅H2O, and metauroxite (IMA2019-030), (UO2)2(C2O4)(OH)2(H2O)2, are the first two uranyl oxalate minerals. Uroxite was found in the Markey mine, Red Canyon, San Juan County, Utah, USA and in the Burro mine, Slick Rock district, San Miguel County, Colorado, USA. Metauroxite was found only in the Burro mine. Both minerals are post-mining secondary phases found in efflorescent crusts on mine walls. Uroxite occurs as light yellow striated blades exhibiting moderate neon-green fluorescence, ca 2 Mohs hardness with good {101} and {010} cleavages. Calculated density = 4.187 g/cm3. Optics are: biaxial (–), α = 1.602(2), β = 1.660(2), γ = 1.680(2) (white light), 2Vmeas. = 59(1)°, 2Vcalc = 59.1°, moderate r > v dispersion, orientation Y = b, Z ∧ a = 35° in obtuse β and it is nonpleochroic. Metauroxite occurs as light yellow crude blades and tablets exhibiting weak green–grey fluorescence, ca 2 Mohs hardness with good {001} cleavage. Calculated density = 4.403 g/cm3. Approximate optics are: α′ = 1.615(5) and γ′ = 1.685(5). Electron probe microanalysis provided UO3 79.60, C2O3 10.02, H2O 10.03, total 99.65 wt.% for uroxite and UO3 82.66, C2O3 10.40, H2O 7.81, total 100.87 wt.% for metauroxite; C2O3 and H2O are based on the structures. Uroxite is monoclinic, P21/c, a = 5.5698(2), b = 15.2877(6), c = 13.3724(9) Å, β = 94.015(7)°, V = 1135.86(10) Å3 and Z = 4. Metauroxite is triclinic, P${\bar 1}$, a = 5.5635(3), b = 6.1152(4), c = 7.8283(4) Å, α = 85.572(5), β = 89.340(4), γ = 82.468°, V = 263.25(3) Å3 and Z = 1. The strongest reflections of the powder XRD pattern [d, Å (I, %)(hkl)] are for uroxite: 10.05(38)(011), 5.00(100)(022, ${\bar 1}$11), 4.75(23)(031), 4.43(51)(120, ${\bar 1}$02), 3.567(33)(131), 3.341(29)(033, ${\bar 1}$32, 004), 2.623(28)(${\bar 2}$02, 015, ${\bar 1}$43, 220) and for metauroxite: 6.06(45)(010), 5.52(33)(100), 4.97(34)(011), 4.52(100)(0${\bar 1}$1, 101), 3.888(80)(111, 002, ${\bar 1}$10), 3.180(51)(${\bar 1}$02, 0${\bar 1}$2), 2.604(32)(${\bar 2}$01, ${\bar 1}$${\bar 2}$1). In the structure of uroxite (R1 = 0.0333 for 2081 I > 2σI reflections), UO7 pentagonal bipyramids share corners forming [U4O24] tetramers, which are linked by C2O4 groups to form corrugated sheets. In the structure of metauroxite (R1 = 0.0648 for 1602 I > 2σI reflections) UO7 pentagonal bipyramids share edges forming [U2O12] dimers, which are linked by C2O4 groups to form zigzag chains.


2018 ◽  
Vol 83 (02) ◽  
pp. 153-160 ◽  
Author(s):  
Anthony R. Kampf ◽  
Travis A. Olds ◽  
Jakub Plášil ◽  
Joe Marty ◽  
Samuel N. Perry

AbstractThe new mineral feynmanite, Na(UO2)(SO4)(OH)·3.5H2O, 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–3. Crystals are thin needles or blades, flattened on {010} and elongate on [100], exhibiting the forms {010}, {001}, {101} and {10$\bar{1}$}, 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); 2Vmeas.= 62(2)°; no dispersion; and optical orientation:X=b,Y≈a,Z≈c. It is weakly pleochroic:X= colourless,Y= very pale green yellow andZ= pale green yellow (X<Y<Z). Electron microprobe analyses (WDS mode) provided (Na0.84Fe0.01)(U1.01O2)(S1.01O4)(OH)·3.5H2O. The five strongest powder X-ray diffraction lines are [dobsÅ(I)(hkl)]: 8.37(100)(010), 6.37(33)($\bar{1}$01,101), 5.07(27)($\bar{1}$11,111), 4.053(46)(004,021) and 3.578(34)(120). Feynmanite is monoclinic, has space groupP2/n,a= 6.927(3),b= 8.355(4),c= 16.210(7) Å, β = 90.543(4)°,V= 938.1(7) Å3andZ= 4. The structure of feynmanite (R1= 0.0371 for 1879Io> 2σI) contains edge-sharing pairs of pentagonal bipyramids that are linked by sharing corners with SO4groups, yielding a [(UO2)2(SO4)2(OH)2]2–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.


2018 ◽  
Vol 82 (2) ◽  
pp. 401-411 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Barbara P. Nash ◽  
Joe Marty

ABSTRACTThe new mineral greenlizardite (IMA2017-001), (NH4)Na(UO2)2(SO4)2(OH)2·4H2O, was found in the Green Lizard mine, Red Canyon, San Juan County, Utah, USA, where it occurs as a secondary alteration phase. It is associated with ammoniozippeite, boussingaultite and dickite. It forms as light green-yellow blades up to ~0.3 mm long. The mineral is vitreous and transparent with a white streak. It fluoresces greenish blue in 405 nm light. Mohs hardness is ~2. Crystals are brittle with irregular fracture and two cleavages: perfect {001} and good {2$\bar 1$0}. Greenlizardite is easily soluble in room-temperature H2O. The calculated density is 3.469 g cm–3. Optically, it is biaxial (+) with α = 1.559(1), β = 1.582(1) and γ = 1.608(1) (measured in white light). The measured 2V is 88(1)°; the calculated 2V is 87.8°. Dispersion is moderate, r < v. Pleochroism is X = very pale yellow green, Y = pale yellow green and Z = light yellow green; X < Y < Z. The optical orientation is X ≈ c, Y ≈ a and Z ≈ b*. The Raman spectrum exhibits bands attributable to both sulfate and uranyl groups. Electron probe microanalyses (with H2O based on the crystal structure) yielded (NH4)0.98Na1.00U1.96S2.04O18.00H10.02. Greenlizardite is triclinic, P$\bar 1$, a = 6.83617(17), b = 9.5127(3), c = 13.8979(10) Å, α = 98.636(7), β = 93.713(7), γ = 110.102(8)°, V = 832.49(8) Å3 and Z = 2. The crystal structure (R1 = 2.39% for 2542 I > 2σI) contains edge-sharing dimers of UO7 pentagonal bipyramids. The dimers link by sharing corners with SO4 groups to form a [(UO2)2(SO4)2(OH)2]2– sheet based on the phosphuranylite anion topology. Zig-zag edge-sharing chains of NaO6 octahedra link adjacent [(UO2)2(SO4)2(OH)2]2– sheets, forming thick slabs. NH4 bonds to O atoms in adjacent slabs linking them together. H2O groups occupy channels in the slabs and space between the slabs.


2020 ◽  
Vol 84 (3) ◽  
pp. 435-443
Author(s):  
Anthony R. Kampf ◽  
Travis A. Olds ◽  
Jakub Plášil ◽  
Barbara P. Nash ◽  
Joe Marty

AbstractThe new mineral pseudomeisserite-(NH4) (IMA2018-166), (NH4,K)2Na4[(UO2)2(SO4)5]⋅4H2O, was found in the Blue Lizard mine, San Juan County, Utah, USA, where it occurs as light yellow prisms in a secondary assemblage with belakovskiite, blödite, changoite, ferrinatrite, gypsum, ivsite, metavoltine and tamarugite. The streak is very pale yellow and the fluorescence is bright lime green under 405 nm ultraviolet light. Crystals are transparent with vitreous lustre. The tenacity is brittle, the Mohs hardness is 2½, the fracture is curved or conchoidal and there is one perfect cleavage on {100}. The mineral is easily soluble in H2O and has a measured density of 3.22(2) g⋅cm–3. Pseudomeisserite-(NH4) is optically biaxial (–) with α = 1.536(2), β = 1.559(2) and γ = 1.565(2) (white light); 2Vmeas. = 53(1)°; dispersion is r > v, distinct; pleochroism: X colourless, Y light yellow and Z pale yellow (X < Z < Y); optical orientation: Z = b, Y ∧ c = 33° in obtuse β). Electron microprobe analyses (WDS mode) provided (NH4)1.49K0.60Na3.87U2.00S5.04O28H7.78. The five strongest X-ray powder diffraction lines are [dobs, Å(I)(hkl)]: 12.69(76)(100), 6.83(84)(012,102), 6.01(100)($\bar{2}$02), 3.959(67)($\bar{2}$21,$\bar{2}$14,$\bar{1}$23) and 3.135(76)($\bar{2}$06,223,$\bar{1}$16). Pseudomeisserite-(NH4) is monoclinic, P21/c, a = 13.1010(3), b = 10.0948(2), c = 19.4945(14) Å, β = 104.285(7)°, V = 2498.5(2) Å3 and Z = 4. The structural unit in the structure (R1 = 0.0254 for 3837 I > 2σI reflections) is a novel [(UO2)2(SO4)5]6– uranyl-sulfate band.


2019 ◽  
Vol 83 (6) ◽  
pp. 799-808 ◽  
Author(s):  
Anthony R. Kampf ◽  
Travis A. Olds ◽  
Jakub Plášil ◽  
Barbara P. Nash ◽  
Joe Marty

AbstractThe new mineral lussierite (IMA2018-101), Na10[(UO2)(SO4)4](SO4)2(H2O)3, was found in the Blue Lizard mine, San Juan County, Utah, USA, where it occurs as pale green–yellow prisms or blades in a secondary assemblage with belakovskiite, ferrinatrite, halite, ivsite, metavoltine and thénardite. The streak is white and the fluorescence is bright cyan under 365 nm ultraviolet light. Crystals are transparent with vitreous lustre. The tenacity is brittle, the Mohs hardness is 2½, the fracture is irregular and no cleavage was observed. The mineral is easily soluble in H2O and has a measured density of 2.87(2) g cm–3. Lussierite is optically biaxial (+), with α = 1.493(1), β = 1.505(1) and γ = 1.518(1) (white light); 2Vmeas.= 88(1)°; dispersion isr>v, moderate; pleochroism:X= colourless,YandZ= green yellow (X<Y≈Z); optical orientation:X=b,Z∧a= 44° in obtuse β. Electron microprobe analyses (wavelength-dispersive spectroscopy mode) provided Na10(U0.99O2)(S1.00O4)6·3H2O (+0.06 H for charge balance). The five strongest X-ray powder diffraction lines are [dobsÅ(I)(hkl)]: 6.69(95)($\bar{1}$11,130), 4.814(100)(150,002,060), 3.461(83)(171,$\bar{2}$02), 2.955(81)(113,330) and 2.882(74)($\bar{1}$91,311,191,0·10·0). Lussierite is monoclinic,Cc,a= 9.3134(4),b= 28.7501(11),c= 9.6346(7) Å, β = 93.442(7)°,V= 2575.1(2) Å3andZ= 4. The structure (R1= 0.0298 for 5202I> 2σI) contains a [(UO2)(SO4)4]6–uranyl sulfate cluster in which one SO4tetrahedron shares an edge (bidentate linkage) with the UO7pentagonal bipyramid. The uranyl sulfate clusters occur in layers and are linked through a complex network of bonds involving Na+cations, isolated SO4tetrahedra and isolated H2O groups.


2017 ◽  
Vol 81 (2) ◽  
pp. 273-285 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Anatoly V. Kasatkin ◽  
Joe Marty ◽  
Jiří Čejka ◽  
...  

AbstractThe new mineral shumwayite (IMA2015-058), [(UO2)(SO4)(H2O)2]2·H2O, was found in the Green Lizard and Giveaway-Simplot mines, White Canyon district, San Juan County, Utah, USA, where it occurs as a secondary alteration phase. At the Green Lizard mine, it is found in association with calcite, gypsum, plášilite, pyrite, rozenite and sulfur; at the Giveaway-Simplot mine, shumwayite is associated with rhomboclase and römerite. The mineral occurs as pale greenish-yellow monoclinic prisms, elongated on [100], up to ∼0.3 mm long and commonly in subparallel to random intergrowths. The mineral is transparent with a vitreous lustre and has a white streak. It fluoresces bright greenish white under both longwave and shortwave ultraviolet radiation. The Mohs hardness is ∼2. Crystals are brittle with perfect {011} cleavage and irregular fracture. The mineral is slightly deliquescent and is easily soluble in room temperature H2O. The calculated density is 3.844 g cm–3. Optically, shumwayite is biaxial (+/–), with α = 1.581(1), β= 1.588(1), γ = 1.595(1) (measured in white light). The measured 2Vxbased on extinction data collected on a spindle stage is 89.8(8)°; the calculated 2Vxis 89.6°. Dispersion is strong, but the sense is not defined because the optic sign is ambiguous. No pleochroism was observed. The optical orientation isX=b,Y=c,Z=a. Energy-dispersive spectrometer analyses (with H2O based on the crystal structure) yielded the empirical formula U2.01S1.99O12.00·5H2O.Shumwayite is monoclinic,P21/c,a= 6.74747(15),b= 12.5026(3),c= 16.9032(12) Å, β = 90.919(6)°,V= 1425.79(11) Å3andZ= 4. The crystal structure (R1= 1.88% for 2936F> 4σF) contains UO7pentagonal bipyramids and SO4tetrahedra that link by corner-sharing to form [(UO2)(SO4)(H2O)2] chains along [100]. The chains and isolated H2O groups between them are linked together only by hydrogen bonds. The mineral is named in honour of the Shumway family, whose members account for the discovery and mining of hundreds of uranium deposits on the Colorado Plateau, including the Green Lizard mine.


2014 ◽  
Vol 78 (3) ◽  
pp. 639-649 ◽  
Author(s):  
A. R. Kampf ◽  
J. Plášil ◽  
A. V. Kasatkin ◽  
J. Marty

AbstractThe new mineral belakovskiite (IMA2013-075), Na7(UO2)(SO4)4(SO3OH)(H2O)3, was found in the Blue Lizard mine, Red Canyon, White Canyon district, San Juan County, Utah, USA, where it occurs as a secondary alteration phase in association with blödite, ferrinatrite, kröhnkite, meisserite and metavoltine. Crystals of belakovskiite are very pale yellowish-green hair-like fibres up to 2 mm long and usually no more than a few mm in diameter. The fibres are elongated on [100] and slightly flattened on {021}. Crystals are transparent with a vitreous lustre. The mineral has a white streak and a probable Mohs hardness of ∼2. Fibres are flexible and elastic, with brittle failure and irregular fracture. No cleavage was observed. The mineral is readily soluble in cold H2O. The calculated density is 2.953 g cm−3. Optically, belakovskiite is biaxial (+) with α = 1.500(1), β = 1.511(1) and γ = 1.523(1) (measured in white light). The measured 2V is 87.1(6)° and the calculated 2V is 88°. The mineral is non-pleochroic. The partially determined optical orientation is X ≈ a. Electron-microprobe analysis provided Na2O 21.67, UO3 30.48, SO3 40.86, H2O 6.45 (structure), total 99.46 wt.% yielding the empirical formula Na6.83(U1.04O2)(SO4)4(S0.99O3OH)(H2O)3 based on 25 O a.p.f.u. Belakovskiite is triclinic, P, with a = 5.4581(3), b = 11.3288(6), c = 18.4163(13) Å, α = 104.786(7)°, β = 90.092(6)°, γ = 96.767(7)°, V = 1092.76(11) Å3 and Z = 2. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 8.96(35)(002), 8.46(29)(011), 5.19(100)(01,101,10), 4.66(58)(013,02,0,110), 3.568(37)(120,023,005,03), 3.057(59)(06,15,31), 2.930(27)(multiple) and 1.8320(29)(multiple). The structure, refined to R1 = 5.39% for 3163 Fo > 4σF reflections, contains [(UO2)(SO4)4(H2O)]6− polyhedral clusters connected via an extensive network of Na−O bonds and H bonds involving eight Na sites, three other H2O sites and an SO3OH (hydrosulfate) group. The 3-D framework, thus defined, is unique among known uranyl sulfate structures. The mineral is named for Dmitry Ilych Belakovskiy, a prominent Russian mineralogist and Curator of the Fersman Mineralogical Museum.


2017 ◽  
Vol 81 (4) ◽  
pp. 753-779 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Anatoly V. Kasatkin ◽  
Joe Marty ◽  
Jiří Čejka

AbstractThe new minerals klaprothite (IMA2015-087), Na6(UO2)(SO4)4(H2O)4, péligotite (IMA2015-088), Na6(UO2)(SO4)4(H2O)4and ottohahnite (IMA2015-098),Na6(UO2)2(SO4)5(H2O)7·1.5H2O, were found in the Blue Lizard mine, San Juan County, Utah, USA, where they occur together as secondary phases. All three minerals occur as yellowish-green to greenish-yellow crystals, are brittle with irregular fracture, have Mohs hardness of ∼2½ and exhibit bright bluish-green fluorescence, and all are easily soluble in room temperature H2O. Only klaprothite exhibits cleavage; perfect on {100} and {001}. Quantitative energydispersive spectroscopy analyses yielded the empirical formulas Na6.01(U1.03O2)(S0.993O4)4(H2O)4, Na5.82(U1.02O2)(S1.003O4)4(H2O)4and Na5.88(U0.99O2)2(S1.008O4)5(H2O)8.5for klaprothite, péligotite and ottohahnite, respectively. Their Raman spectra exhibit similar features. Klaprothite is monoclinic,P21/c,a= 9.8271(4),b= 9.7452(3),c= 20.8725(15) Å, β = 98.743(7)°,V= 1975.66(17)Å3andZ= 4. Péligotite is triclinic,P1̄,a= 9.81511(18),b= 9.9575(2),c= 10.6289(8) Å, α = 88.680(6)°, β = 73.990(5)°, γ = 89.205(6)°,V= 998.22(8) Å3andZ=2. Ottohahnite is triclinic,P1̄,a= 9.97562(19),b= 11.6741(2),c= 14.2903(10) Å, α = 113.518(8)°, β = 104.282(7)°, γ = 91.400(6)°,V= 1464.59(14) Å3andZ= 2. The structures of klaprothite(R1= 2.22%) and péligotite (R1= 2.28%) both contain [(UO2)(SO4)4]6–clusters in which one SO4group has a bidentate linkage with the UO7polyhedron; Na–O polyhedra linkclusters into thick heteropolyhedral layers and link layers into frameworks; the structures differ in the configuration of Na–O polyhedra that link the layers. The structure of ottohahnite (R1= 2.65%) contains [(UO2)4(SO4)10]12–clusters in which each UO7polyhedron has a bidentate linkage with one SO4group; Na–O polyhedra link clusters into a thin heteropolyhedral slice and also link the slices into a framework. The minerals are named for Martin Heinrich Klaproth (1743–1817), Eugène-MelchiorPéligot (1811–1890) and Otto Hahn (1879–1968).


2017 ◽  
Vol 81 (4) ◽  
pp. 895-907 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Jiří Čejka ◽  
Joe Marty ◽  
Radek Škoda ◽  
...  

AbstractThe new mineral alwilkinsite-(Y) (IMA2015-097), Y(H2O)7[(UO2)3(SO4)2O(OH)3]·7H2O, was found in the Blue Lizard mine, San Juan County, Utah, USA, where it occurs as a secondary alteration phase.The mineral is slightly flexible before brittle failure with splintery fracture and perfect cleavage parallel to [010], has Mohs hardness of ∼2–2½, exhibits dull greenish-grey fluorescence and has a calculated density of 3.371 g cm–3. Alwilkinsite-(Y) occursas yellowish-green needles, elongate on [010], with domatic terminations and exhibits the forms {102}, {301} and {124}. It is optically biaxial (+) with α = 1.573(1), β = 1.581(1), γ = 1.601(1) (white light), the measured 2V is 65.3(1)°, the dispersion is r<v (weak), the optical orientation is X = c, Y = a, Z = b and there is no pleochroism. Electron microprobe analyses yielded the empirical formula (Y0.66Dy0.08Gd0.06Er0.05Nd0.03Yb0.03Sm0.02Ce0.01)∑0.94(H2O)7[(UO2)3(S1.01O4)2O(OH)3]·7H2O.The eight strongest powder X-ray diffraction lines are [dobs Å(I)(hkl)]: 9.88(100)(101,002), 7.47(13)(102), 5.621(17)(103,201), 4.483(18)(104), 3.886(14)(130,222), 3.322(46)(multiple), 3.223(13)(multiple) and 3.145(16)(034). Alwilkinsite-(Y) is orthorhombic,P212121, a = 11.6194(5), b = 12.4250(6), c = 19.4495(14) Å, V = 2807.9(3) Å3 and Z = 4. The structure of alwilkinsite-(Y) (R1 = 0.042 for 4244 Fo > 4σF)contains edge-sharing chains of uranyl bipyramids with outlying sulfate tetrahedra that are similar to the chain linkages within the uranyl sulfate sheets of the zippeite structure. Short segments of the uranyl sulfate chains in the alwilkinsite-(Y) structure have the same topology as portionsof the uranyl sulfate linkages in uranopilite. Alwilkinsite-(Y) is named for Alan (Al) J. Wilkins, MD (born 1955), the discoverer of the mineral.


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