Ammoniomathesiusite, a new uranyl sulfate–vanadate mineral from the Burro mine, San Miguel County, Colorado, USA

2018 ◽  
Vol 83 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Barbara P. Nash ◽  
Joe Marty
Keyword(s):  
Secondary Phase ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Green Fluorescence ◽  
Uranyl Sulfate ◽  
Calculated Density ◽  
X Ray ◽  
Pale Yellow ◽  
Bright Yellow ◽  
Mohs Hardness

AbstractThe new mineral ammoniomathesiusite (NH4)5(UO2)4(SO4)4(VO5)·4H2O, 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/cm3. Ammoniomathesiusite is optically uniaxial (–) with ω = 1.653(2) and ε = 1.609(2) (white light). Pleochroism is: O = green-yellow, E = colourless; O > E. Electron microprobe analyses yielded the empirical formula [(NH4)4.75(UO2)4(SO4)4(VO5)·4(H2.07O). The five strongest powder X-ray diffraction lines are [dobs Å(I)(hkl)]: 10.57(46)(110), 7.10(62)(001), 6.41(100)(101), 3.340(35)(240) and 3.226(44)(141). Ammoniomathesiusite is tetragonal, P4/n with a = 14.9405(9), c = 7.1020(5) Å, V = 1585.3(2) Å3 and Z = 2. The structure of ammoniomathesiusite (R1 = 0.0218 for 3427 I > 2σI) contains heteropolyhedral sheets based on [(UO2)4(SO4)4(VO5)]5– clusters. The structure is identical to that of mathesiusite, with ${\rm NH}_{\rm 4}^{\rm +} $ in place of K+.

Magnesiocanutite, NaMnMg2[AsO4]2[AsO2(OH)2], a new protonated alluaudite-group mineral from the Torrecillas mine, Iquique Province, Chile

2017 ◽  
Vol 81 (6) ◽  
pp. 1523-1531 ◽  
Author(s):  
Anthony R. Kampf ◽  
Barbara P. Nash ◽  
Dini Maurizio ◽  
Arturo A. Molina Donoso
Keyword(s):  
Structure Refinement ◽  
Secondary Phase ◽  
Obtuse Angle ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Crystal Forms ◽  
X Ray ◽  
Temperature Electron ◽  
Mohs Hardness

AbstractThe new mineral magnesiocanutite (IMA2016-057), NaMnMg2[AsO4]2[AsO2(OH)2], was found at the Torrecillas mine, Iquique Province, Chile, where it occurs as a secondary phase in association with anhydrite, canutite, halite, lavendulan and magnesiokoritnigite. Magnesiocanutite occurs as pale brownish-pink to rose-pink, lozenge-shaped tablets that are often grouped in tightly intergrown aggregates. The crystal forms are {110} and {102}. Crystals are transparent, with vitreous lustre and white to very pale pink streak. The Mohs hardness is 2½, tenacity is brittle, and the fracture is splintery. Crystals exhibit two perfect cleavages: {010} and {101}. The calculated density is 3.957 g/cm3. Optically, magnesiocanutite is biaxial (+), with α = 1.689(2), β = 1.700(2), γ = 1.730(2) (measured in white light); 2Vmeas. = 64.3(4)°; slight dispersion, r <v; orientation Z = b; X ∧ a = 15° in obtuse angle β. The mineral is slowly soluble in dilute HCl at room temperature. Electron-microprobe analyses, provided Na2O 5.44, CaO 0.26, MgO 8.84, MnO 18.45, CoO 1.47, CuO 2.13, As2O5 59.51, H2O(calc) 2.86, total 98.96 wt.%. Magnesiocanutite is monoclinic, C2/c, a = 12.2514(8), b = 12.4980(9), c = 6.8345(5) Å, β = 113.167(8)°, V = 962.10(13) Å3 and Z = 4. The eight strongest powder X-ray diffraction lines are [dobs Å(I )(hkl)]: 6.25(42)(020), 3.566(43)(310,1̄31), 3.262(96)(1̄12), 3.120(59)(002,131,040,221), 2.787(93)(400,022,041,330), 2.718(100) (4̄21,240,112,402), 2.641(42)(1̄32) and 1.5026(43)(multiple). Magnesiocanutite has a protonated alluaudite-type structure (R1 = 2.59% for 789 Fo > 4σF reflections) and is the Mg analogue of canutite. Using the results of both the microprobe analyses and structure refinement, the structurally based empirical formula is Na(Mn0.78Mg0.22)Σ1.00(Mg1.04Mn0.70Cu0.15Co0.11)Σ2.00[AsO4]2[AsO2(OH)2].

Alwilkinsite-(Y), a new rare-earth uranyl sulfate mineral from the Blue Lizard mine, San Juan County, Utah, USA

2017 ◽  
Vol 81 (4) ◽  
pp. 895-907 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Jiří Čejka ◽  
Joe Marty ◽  
Radek Škoda ◽  
...  
Keyword(s):  
New Mineral ◽  
San Juan ◽  
X Ray Diffraction ◽  
Uranyl Sulfate ◽  
Calculated Density ◽  
Secondary Alteration ◽  
X Ray ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
San Juan County

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.

Hrabákite, Ni9PbSbS8, a new member of the hauchecornite group from Příbram, Czech Republic

2021 ◽  
pp. 1-8
Author(s):  
Jiří Sejkora ◽  
Pavel Škácha ◽  
Jakub Plášil ◽  
Zdeněk Dolníček ◽  
Jana Ulmanová
Keyword(s):  
Czech Republic ◽  
Diffraction Data ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
X Ray ◽  
Reflected Light ◽  
Mohs Hardness ◽  
Cation Sites ◽  
The Ideal

Abstract The new mineral hrabákite (IMA2020-034) was found in siderite–sphalerite gangue with minor dolomite–ankerite at the dump of shaft No. 9, one of the mines in the abandoned Příbram uranium and base-metal district, central Bohemia, Czech Republic. Hrabákite is associated with Pb-rich tučekite, Hg-rich silver, stephanite, nickeline, millerite, gersdorffite, sphalerite and galena. The new mineral occurs as rare prismatic crystals up to 120 μm in size and allotriomorphic grains. Hrabákite is grey with a brownish tint. Mohs hardness is ca. 5–6; the calculated density is 6.37 g.cm–3. In reflected light, hrabákite is grey with a brown hue. Bireflectance is weak and pleochroism was not observed. Anisotropy under crossed polars is very weak (brownish tints) to absent. Internal reflections were not observed. Reflectance values of hrabákite in air (Rmin–Rmax, %) are: 39.6–42.5 at 470 nm, 45.0–47.5 at 546 nm, 46.9–49.2 at 589 nm and 48.9–51.2 at 650 nm). The empirical formula for hrabákite, based on electron-microprobe analyses (n = 11), is (Ni8.91Co0.09Fe0.03)9.03(Pb0.94Hg0.04)0.98(Sb0.91As0.08)0.99S7.99. The ideal formula is Ni9PbSbS8, which requires Ni 47.44, Pb 18.60, Sb 10.93 and S 23.03, total of 100.00 wt.%. Hrabákite is tetragonal, P4/mmm, a = 7.3085(4), c = 5.3969(3) Å, with V = 288.27(3) Å3 and Z = 1. The strongest reflections of the calculated powder X-ray diffraction pattern [d, Å (I)(hkl)] are: 3.6543(57)(200); 3.2685(68)(210); 2.7957(100)(211); 2.3920(87)(112); 2.3112(78)(310); 1.8663(74)(222); and 1.8083(71)(302). According to the single-crystal X-ray diffraction data (Rint = 0.0218), the unit cell of hrabákite is undoubtedly similar to the cell reported for tučekite. The structure contains four metal cation sites, two Sb (Sb1 dominated by Pb2+) and two Ni (with minor Co2+ content) sites. The close similarity in metrics between hrabákite and tučekite is due to similar bond lengths of Pb–S and Sb–S pairs. Hrabákite is named after Josef Hrabák, the former professor of the Příbram Mining College.

Sergevanite, Na15(Ca3Mn3)(Na2Fe)Zr3Si26O72(OH)3·H2O, a new eudialyte-group mineral from the Lovozero alkaline massif, Kola Peninsula

2020 ◽  
Vol 58 (4) ◽  
pp. 421-436 ◽  
Author(s):  
Nikita V. Chukanov ◽  
Sergey M. Aksenov ◽  
Igor V. Pekov ◽  
Dmitriy I. Belakovskiy ◽  
Svetlana A. Vozchikova ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Structural Data ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Eudialyte Group ◽  
Group Mineral ◽  
X Ray ◽  
Mohs Hardness ◽  
Alkaline Massif

ABSTRACT The new eudialyte-group mineral sergevanite, ideally Na15(Ca3Mn3)(Na2Fe)Zr3Si26O72(OH)3·H2O, was discovered in highly agpaitic foyaite from the Karnasurt Mountain, Lovozero alkaline massif, Kola Peninsula, Russia. The associated minerals are microcline, albite, nepheline, arfvedsonite, aegirine, lamprophyllite, fluorapatite, steenstrupine-(Ce), ilmenite, and sphalerite. Sergevanite forms yellow to orange-yellow anhedral grains up to 1.5 mm across and the outer zones of some grains of associated eudialyte. Its luster is vitreous, and the streak is white. No cleavage is observed. The Mohs' hardness is 5. Density measured by equilibration in heavy liquids is 2.90(1) g/cm3. Calculated density is equal to 2.906 g/cm3. Sergevanite is nonpleochroic, optically uniaxial, positive, with ω = 1.604(2) and ε = 1.607(2) (λ = 589 nm). The infrared spectrum is given. The chemical composition of sergevanite is (wt.%; electron microprobe, H2O determined by HCN analysis): Na2O 13.69, K2O 1.40, CaO 7.66, La2O3 0.90, Ce2O3 1.41, Pr2O3 0.33, Nd2O3 0.64, Sm2O3 0.14, MnO 4.15, FeO 1.34, TiO2 1.19, ZrO2 10.67, HfO2 0.29, Nb2O5 1.63, SiO2 49.61, SO3 0.77, Cl 0.23, H2O 4.22, –O=Cl –0.05, total 100.22. The empirical formula (based on 25.5 Si atoms pfu, in accordance with structural data) is H14.46Na13.64K0.92Ca4.22Ce0.27La0.17Nd0.12Pr0.06Sm0.02Mn1.81Fe2+0.58Ti0.46Zr2.67Hf0.04Nb0.38Si25.5S0.30Cl0.20O81.35. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is trigonal, space group R3, with a = 14.2179(1) Å, c = 30.3492(3) Å, V = 5313.11(7) Å3, and Z = 3. In the structure of sergevanite, Ca and Mn are ordered in the six-membered ring of octahedra (at the sites M11 and M12), and Na dominates over Fe2+ at the M2 site. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 7.12 (70) (110), 5.711 (43) (202), 4.321 (72) (205), 3.806 (39) (033), 3.551 (39) (220, 027), 3.398 (39) (313), 2.978 (95) (), 2.855 (100) (404). Sergevanite is named after the Sergevan' River, which is near the discovery locality.

Pseudomeisserite-(NH4), a new mineral with a novel uranyl-sulfate linkage from the Blue Lizard mine, San Juan County, Utah, USA

2020 ◽  
Vol 84 (3) ◽  
pp. 435-443
Author(s):  
Anthony R. Kampf ◽  
Travis A. Olds ◽  
Jakub Plášil ◽  
Barbara P. Nash ◽  
Joe Marty
Keyword(s):  
New Mineral ◽  
San Juan ◽  
Optical Orientation ◽  
Uranyl Sulfate ◽  
X Ray ◽  
Pale Yellow ◽  
Light Yellow ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
San Juan County

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.

Flamite, (Ca,Na,K)2(Si,P)O4, a new mineral from ultrahightemperature combustion metamorphic rocks, Hatrurim Basin, Negev Desert, Israel

2015 ◽  
Vol 79 (3) ◽  
pp. 583-596 ◽  
Author(s):  
E. V. Sokol ◽  
Y. V. Seryotkin ◽  
S. N. Kokh ◽  
Ye. Vapnik ◽  
E. N. Nigmatulina ◽  
...  
Keyword(s):  
Negev Desert ◽  
Metamorphic Rocks ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
X Ray ◽  
Calcium Silicate Hydrates ◽  
Temperature Combustion ◽  
Mohs Hardness ◽  
Ultrahigh Temperature

AbstractFlamite (Ca,Na,K)2(Si,P)O4 (P63; a = 43.3726(18), c = 6.8270(4) Å; V = 11122.2(9) Å3), a natural analogue of the P,Na,K-doped high-temperature α-Ca2SiO4 modification, is a new mineral from Ca- and Al-rich paralava, an ultrahigh-temperature combustion metamorphic melt rock. The type locality is situated in the southern Hatrurim Basin, the Negev Desert, Israel. Flamite occurs as regular lamellar intergrowths with partially hydrated larnite, together with rock-forming gehlenite, rankinite and Ti-rich andradite, minor ferrian perovskite, magnesioferrite, hematite, and retrograde ettringite and calcium silicate hydrates. The mineral is greyish to yellowish, transparent with a vitreous lustre, non-fluorescent under ultraviolet light and shows no parting or cleavage; Mohs hardness is 5–5½; calculated density is 3.264 g cm–3. The empirical formula of holotype flamite (mean of 21 analyses) is (Ca1.82Na0.09K0.06(Mg,Fe,Sr,Ba)0.02)Σ1.99(Si0.82P0.18)Σ1.00O4. The strongest lines in the powder X-ray diffraction pattern are [d, Å (Iobs)]: 2.713(100), 2.765(44), 2.759(42), 1.762(32), 2.518(29), 2.402(23), 2.897(19), 1.967(18), 2.220(15), 1.813(15). The strongest bands in the Raman spectrum are 170, 260, 520, 538, 850, 863, 885, 952 and 1003 cm–1.

Ferribushmakinite, Pb2Fe3+(PO4)(VO4)(OH), the Fe3+ analogue of bushmakinite from the Silver Coin mine, Valmy, Nevada

2015 ◽  
Vol 79 (3) ◽  
pp. 661-669 ◽  
Author(s):  
A. R. Kampf ◽  
P. M. Adams ◽  
B. P. Nash ◽  
J. Marty
Keyword(s):  
Low Temperature ◽  
Electron Microprobe ◽  
New Mineral ◽  
Secondary Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
X Ray ◽  
Silver Coin ◽  
Humboldt County ◽  
Mohs Hardness

AbstractFerribushmakinite (IMA2014-055), Pb2Fe3+(PO4)(VO4)(OH), the Fe3+ analogue of bushmakinite, is a new mineral from the Silver Coin mine, Valmy, Iron Point district, Humboldt County, Nevada, USA, where it occurs as a low-temperature secondary mineral in association with plumbogummite, mottramite, Br-rich chlorargyrite and baryte on massive quartz. Ferribushmakinite forms yellow slightly flattened prisms up to 0.2 mm long growing in X and sixling twins. The streak is pale yellow. Crystals are translucent and have adamantine lustre. The Mohs hardness is ∼2, the tenacity is brittle, the fracture is irregular to splintery and crystals exhibit one or two fair cleavages in the [010] zone. The calculated density is 6.154 g/cm3. Electron microprobe analyses provided: PbO 63.69, CaO 0.07, CuO 1.11, Fe2O3 7.63, Al2O3 1.63, V2O5 12.65, As2O5 3.09, P2O58.63, H2O 1.50 (structure), total 100.00 wt.% (normalized). The empirical formula (based on nine O a.p.f.u.) is: (Pb1.99Ca0.01)Σ2.00(Fe0.66Al0.22Cu0.10)Σ0.98(V0.97P0.85As0.19)Σ2.01O7.84(OH)1.16. Ferribushmakinite is monoclinic, P21/m, a = 7.7719(10), b = 5.9060(7), c = 8.7929(12) Å, β = 111.604(8)°, V = 375.24(9) Å3 and Z = 2. The eight strongest lines in the powder X-ray diffraction pattern are [dobs in Å (I)(hkl)]: 4.794(46)(011); 3.245(84)(211); 2.947(100)(020,212,103); 2.743(49)(112); 2.288(30)(220); 1.8532(27)(314,403); 1.8084(27)(multiple); and 1.7204(28)(312,114,321). Ferribushmakinite is a member of the brackebuschite supergroup. Its structure (R1 = 3.83% for 577 Fo > 4σF) differs from that of bushmakinite only in the dominance of Fe3+ over Al in the octahedral site.

Gajardoite, KCa0.5As3+4O6Cl2·5H2O, a new mineral related to lucabindiite and torrecillasite from the Torrecillas mine, Iquique Province, Chile

2016 ◽  
Vol 80 (7) ◽  
pp. 1265-1272 ◽  
Author(s):  
Anthony R. Kampf ◽  
Barbara P. Nash ◽  
Maurizio Dini ◽  
Arturo Molina A. Donoso
Keyword(s):  
Electron Microprobe ◽  
Room Temperature ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Secondary Alteration ◽  
X Ray ◽  
Mohs Hardness ◽  
Measured Density ◽  
Irregular Cleavage

AbstractThe new mineral gajardoite (IMA2015-040), KCa0.5As3+4O6Cl2·5H2O, was found at the Torrecillas mine, Iquique Province, Chile, where it occurs as a secondary alteration phase in association with native arsenic, arsenolite,chongite, talmessite and torrecillasite. Gajardoite occurs as hexagonal plates up to ∼100 μm in diameter and 5 μm thick, in rosette-like subparallel intergrowths. Crystals are transparent, with vitreous lustre and white streak. The Mohs hardness is ∼1½, tenacity is brittleand fracture is irregular. Cleavage is perfect on {001}. The measured density is 2.64 g/cm3 and the calculated density is 2.676 g/cm3. Optically, gajardoite is uniaxial (–) with ω = 1.780(3) and ε = 1.570(5) (measured in white light). The mineral is very slowly soluble in H2O and slowly soluble in dilute HCl at room temperature. The empirical formula, determined from electron-microprobe analyses, is (K0.77Ca0.71Na0.05Mg0.05)∑1.58As4O11Cl1.96H9.62.Gajardoite is hexagonal, P6/mmm, a = 5.2558(8), c = 15.9666(18) Å, V = 381.96(13) Å3 and Z = 1. The eight strongest powder X-ray diffraction lines are [dobs Å(I)(hkl)]: 16.00(100)(001), 5.31(48)(003),3.466 (31)(103), 3.013(44)(104), 2.624(51)(006,110,111), 2.353(36)(113), 1.8647(21)(116,205) and 1.4605(17) (119,303,216). The structure, refined to R1 = 3.49% for 169 Fo > 4σF reflections, contains two types of layers. One layer of formulaKAs3+4O6Cl2 consists of two neutral As2O3 sheets, between which are K+ cations and on the outside of which are Cl– anions. This layer is topologically identical to a slice of the lucabindiite structureand similar to a slice of the torrecillasite structure. The second layer consists of an edge-sharing sheet of Ca(H2O)6 trigonal pyramids with isolated H2O groups centred in the hexagonal cavities in the sheet.

Feynmanite, a new sodium uranyl sulfate mineral from Red Canyon, San Juan County, Utah, USA

2018 ◽  
Vol 83 (02) ◽  
pp. 153-160 ◽  
Author(s):  
Anthony R. Kampf ◽  
Travis A. Olds ◽  
Jakub Plášil ◽  
Joe Marty ◽  
Samuel N. Perry
Keyword(s):  
Secondary Phase ◽  
New Mineral ◽  
San Juan ◽  
Uranyl Sulfate ◽  
Calculated Density ◽  
Laser Crystals ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
San Juan County ◽  
Pale Green

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&lt;Y&lt;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&gt; 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.

Markeyite, a new calcium uranyl carbonate mineral from the Markey mine, San Juan County, Utah, USA

2018 ◽  
Vol 82 (5) ◽  
pp. 1089-1100 ◽  
Author(s):  
Anthony R. Kampf ◽  
Jakub Plášil ◽  
Anatoly V. Kasatkin ◽  
Joe Marty ◽  
Jiří Čejka
Keyword(s):  
Secondary Phase ◽  
New Mineral ◽  
San Juan ◽  
X Ray Diffraction ◽  
X Ray ◽  
Light Yellow ◽  
Uranyl Carbonate ◽  
Laser Crystals ◽  
Mohs Hardness ◽  
San Juan County

ABSTRACTThe new mineral markeyite (IMA2016-090), Ca9(UO2)4(CO3)13·28H2O, was found in the Markey mine, San Juan County, Utah, USA, where it occurs as a secondary phase on asphaltum in association with calcite, gypsum and natrozippeite. The mineral is pale yellowish-green with white streak and fluoresces bright bluish white under a 405 nm laser. Crystals are transparent and have vitreous to pearly lustre. It is brittle, with Mohs hardness 1½ to 2, irregular fracture and three cleavages: perfect on {001}; good on {100} and {010}. The measured density is 2.68 g cm–3. Crystals are blades, flattened on {001} and elongate on [010], exhibiting the forms {100}, {010}, {001}, {110}, {101}, {011} and {111}. Markeyite is optically biaxial (–) with α = 1.538(2), β = 1.542(2) and γ = 1.545(2) (white light); the measured 2V is 81(2)°; the dispersion isr<v(weak); the optical orientation isX=c,Y=b,Z=a; and pleochroism isX= light greenish yellow,YandZ= light yellow (X>Y≈Z). Electron microprobe analyses (energy-dispersive spectroscopy mode) yielded CaO 18.60, UO342.90, CO221.30 (calc.) and H2O 18.78 (calc.), total 101.58 wt.% and the empirical formula Ca8.91(U1.01O2)4(CO3)13·28H2O. The six strongest powder X-ray diffraction lines are [dobsÅ(I)(hkl)]: 10.12(69)(001), 6.41(91)(220,121), 5.43(100)(221), 5.07(33)(301,002,131), 4.104(37)(401,141) and 3.984(34)(222). Markeyite is orthorhombic,Pmmn,a= 17.9688(13),b= 18.4705(6),c= 10.1136(4) Å,V= 3356.6(3) Å3andZ= 2. The structure of markeyite (R1= 0.0435 for 3427Fo> 4σF) contains uranyl tricarbonate clusters (UTC) that are linked by Ca–O polyhedra forming thick corrugated heteropolyhedral layers. Included within the layers is an additional disordered CO3group linking the Ca–O polyhedra. The layers are linked to one another and to interlayer H2O groups only via hydrogen bonds. The structure bears some similarities to that of liebigite.

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