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Darrellhenryite, Na(LiAl2)Al6(BO3)3Si6O18(OH)3O, a new member of the tourmaline supergroup (related to the alkali-subgroup 4), is a new Li-bearing tourmaline species, which is closely related to elbaite through the substitution YAl0.5WO1YLi-0.5W(OH)-1. It occurs in a complex (Li-bearing) petalite-subtype pegmatite with common lepidolite, Li-bearing tourmalines, and amblygonite at Nová Ves near Český Krumlov, southern Bohemia, Moldanubian Zone, Czech Republic. This zoned pegmatite dike cross-cuts a serpentinite body enclosed in leucocratic granulites. Pink darrellhenryite forms columnar crystals (sometimes in parallel arrangement) up to 3 cm long and up 2 cm thick, associated with albite (var. cleavelandite), minor quartz, K-feldspar, petalite, rare polylithionite, and locally rare pollucite. The optical properties and the single-crystal structure study (R1 = 0.019) of darrellhenryite are consistent with trigonal symmetry, ω = 1.636(2), ε = 1.619(2), birefringence: 0.017, space group R3m, a = 15.809(2), c = 7.089(1) Å, V= 1534.4(4) ų, and Z = 3. The chemical analysis, in combination with the results from the single-crystal structure refinement, gives the formula X(Na0.58Ca0.01... 0.41)1.00 Y(Li1.05Al1.95)3.00 ZAl6 (BO3)3 T(Si6O18) V(OH)3 W(O0.66F0.34)1.00, which can be simplified to an ideal formula of Na(LiAl2) Al6(BO3)3Si6O18(OH)3O. The strongest lines of the powder pattern [d in Å (I, hkl)] are 4.180 (39,211), 3.952 (54,220), 3.431 (73, 012), 2.925 (100,122), 2.555 (90, 051), 2.326 (42, 511), 2.029 (42, 223), 2.021 (42,152), 1.901 (50, 342), 1.643 (49, 603). The density isDmeas = 3.03(3) g/cm³,Dcalc = 3.038 g/cm³. Darrellhenryite is considered to have crystallized in Li- and B-rich but F-moderate environments in complex pegmatites; no influence of higher activity of O on the darrellhenryite formation is implied from its mineral assemblage. The name is for Darrell J. Henry, Professor of Geology at the Louisiana State University, Baton Rouge, U.S.A., an expert on the mineralogy, petrology, crystal chemistry, and nomenclature of tourmaline-supergroup minerals. [ABSTRACT FROM AUTHOR]

Oxy-schorl (IMA 2011-011), ideally Na(Fe2+2Al)Al6Si6O18(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup, is described. In Zlatá Idka, Slovak Republic (type locality), fan-shaped aggregates of greenish black acicular crystals ranging up to 2 cm in size, forming aggregates up to 3.5 cm thick were found in extensively metasomatically altered metarhyolite pyroclastics with Qtz+Ab+Ms. In Přibyslavice, Czech Republic (co-type locality), abundant brownish black subhedral, columnar crystals of oxy-schorl, up to 1 cm in size, arranged in thin layers, or irregular clusters up to 5 cm in diameter, occur in a foliated muscovite-tourmaline orthogneiss associated with Kfs+Ab+Qtz+Ms+Bt+Grt. Oxy-schorl from both localities has a Mohs hardness of 7 with no observable cleavage and parting. The measured and calculated densities are 3.17(2) and 3.208 g/cm3 (Zlatá Idka) and 3.19(1) and 3.198 g/cm3 (Přibyslavice), respectively. In plane-polarized light, oxy-schorl is pleochroic; O = green to bluish-green, E = pale yellowish to nearly colorless (Zlatá Idka) and O = dark grayish-green, E = pale brown (Přibyslavice), uniaxial negative, ω = 1.663(2), ε = 1.641(2) (Zlatá Idka) and ω = 1.662(2), ε = 1.637(2) (Přibyslavice). Oxy-schorl is trigonal, space group R3m, Z = 3, a = 15.916(3) Å, c = 7.107(1) Å, V = 1559.1(4) Å3 (Zlatá Idka) and a = 15.985(1) Å, c = 7.154(1) Å, V = 1583.1(2) Å3 (Přibyslavice). The composition (average of 5 electron microprobe analyses from Zlatá Idka and 5 from Přibyslavice) is (in wt%): SiO2 33.85 (34.57), TiO2 <0.05 (0.72), Al2O3 39.08 (33.55), Fe2O3 not determined (0.61), FeO 11.59 (13.07), MnO <0.06 (0.10), MgO 0.04 (0.74), CaO 0.30 (0.09), Na2O 1.67 (1.76), K2O <0.02 (0.03), F 0.26 (0.56), Cl 0.01 (<0.01), B2O3 (calc.) 10.39 (10.11), H2O (from the crystal-structure refinement) 2.92 (2.72), sum 99.29 (98.41) for Zlatá Idka and Přibyslavice (in parentheses). A combination of EMPA, Mössbauer spectroscopy, and crystal-structure refinement yields empirical formulas (Na0.591Ca0.103⇔0.306)Σ1.000(Al1.885Fe2+1.108Mn0.005Ti0.002)Σ3.000(Al5.428Mg0.572)Σ6.000(Si5.506Al0.494)Σ6.000O18 (BO3)3(OH)3(O0.625OH0.236F0.136Cl0.003)Σ1.000 for Zlatá Idka, and (Na0.586Ca0.017K0.006⇔0.391)Σ1.000(Fe2+1.879Mn0.015 Al1.013Ti0.093)Σ3.00(Al5.732Mg0.190Fe3+0.078)Σ6.000(Si5.944Al0.056)Σ6.000O18(BO3)3(OH)3(O0.579F0.307OH0.115)Σ1.000 for Přibyslavice. Oxy-schorl is derived from schorl end-member by the AlOFe-1(OH)-1 substitution. The studied crystals of oxy-schorl represent two distinct ordering mechanisms: disorder of R2+ and R3+ cations in octahedral sites and all O ordered in the W site (Zlatá Idka), and R2+ and R3+ cations ordered in the Y and Z sites and O disordered in the V and W sites (Přibyslavice). [ABSTRACT FROM AUTHOR]

Adolfpateraite, monoclinic K(UO2)(SO4)(OH)(H2O), is a new supergene mineral from the Svornost mine, Jáchymov ore district, Czech Republic. It forms sulfur yellow to greenish yellow crystalline aggregates, up to 2 mm in diameter. Crystals are transparent to translucent with a vitreous luster, without observable cleavage. The streak is pale yellow. The Mohs hardness is ~2. The mineral shows a green fluorescence in long-wave ultraviolet radiation. Adolfpateraite is pleochroic, with a = colorless and γ = yellow (β could not been examined). It is biaxial, with α = 1.597(2), γ = 1.659(2) (β could not been measured), birefringence 0.062. The empirical chemical formula (mean of 4 electron microprobe point analyses) was calculated based on 8 O apfu and is K0.94(UO2)1.00 (SO4)1.02(OH)0.90 (H2O)1.00 (water content calculated). The simplified formula is K(UO2)(SO4)(OH)(H2O), requiring K2O 10.70, UO3 64.97, SO3 18.19, H2O 6.14, total 100.00 wt%. Adolfpateraite is monoclinic, space group P21/c, a = 8.0462(1), b = 7.9256(1), c = 11.3206(2) Å, β = 107.726(2)°, V = 687.65(2) ų, Z = 4, and Dcalc = 4.24 g/cm³. The five strongest reflections in the X-ray powder diffraction pattern are [dobs in Å (I) (hkl)]: 7.658 (76) (100), 5.386 (1̅00) (002), 5.218 (85) (102), 3.718 (46) (021), 3.700 (37) (2̅02). The crystal structure has been refined from single-crystal X-ray diffraction data to R1 = 0.0166 with GOF = 1.30, based on 1915 observed reflections [Iobs > 3σ(I)]. The crystal structure consists of chains of uranyl polyhedra extended along [010], with OH- located on the shared vertex between the bipyramids. The sulfate tetrahedra decorate the outer side of the chain with bridging bidentate linkages between the uranyl pentagonal bipyramids. H2O groups are located on the edges of the chains on the non-linking vertex of each uranyl pentagonal bipyramid. K+ atoms are located between the chains providing additional linkage of these together with H-bonds. The fundamental vibrational modes of uranyl ion, sulfate tetrahedra, and H2O groups were tentatively assigned in the infrared and Raman spectra. The new mineral is named to honor Adolf Patera (1819-1894), Czech chemist, mineralogist, and metallurgist. [ABSTRACT FROM AUTHOR]

Sejkoraite-(Y), the triclinic Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed., is a new member of the zippeite group from the Cervená vein, Jáchymov (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 α' = 1.62(2), β' = 1.662(3), γ' = 1.73(1), 2Vcalc = 79°. The empirical chemical formula (mean of 8 electron microprobe point analyses) was calculated on the basis of 12 (S + U) atoms: Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. Sejkoraite-(Y) is triclinic, space group P1̄, a = 14.0743(6), b = 17.4174(7), c = 17.7062(8) Å, α = 75.933(4), β = 128.001(5), γ = 74.419(4)°, V = 2777.00(19) Å , Z = 2, Dcalc = 4.04 g/cm³. The seven strongest reflections in the X-ray powder diffraction pattern are [dobs in Å (I) (hkl)]: 9.28 (100) (100), 4.64 (39) (200), 3.631 (6) (1̄42), 3.451 (13) (1̄44), 3.385 (10) (24̅2), 3.292 (9) (044), 3.904(7) (300), 2.984 (10) (1̄4̄2). 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), Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. 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 Jiří Sejkora, a Czech mineralogist of the National Museum in Prague. [ABSTRACT FROM AUTHOR]

Mathesiusite, K5(UO2)4(SO4)4(VO5)(H2O)4, a new uranyl vanadate-sulfate mineral from Jáchymov, Western Bohemia, Czech Republic, occurs on fractures of gangue associated with adolfpateraite, schoepite, čejkaite, zippeite, gypsum, and a new unnamed K-UO2-SO4 mineral. It is a secondary mineral formed during post-mining processes. Mathesiusite is tetragonal, space group P4/n, with the unit-cell dimensions a = 14.9704(10), c = 6.8170(5) Å, V = 1527.78(18) ų, and Z = 2. Acicular aggregates of mathesiusite consist of prismatic crystals up to ~200 μm long and several micrometers thick. It is yellowish green with a greenish white streak and vitreous luster. The Mohs hardness is ~2. Mathesiusite is brittle with an uneven fracture and perfect cleavage on {110} and weaker on {001}. The calculated density based on the empirical formula is 4.02 g/cm3. Mathesiusite is colorless in fragments, uniaxial (-), with ω = 1.634(3) and ε = 1.597(3). Electron microprobe analyses (average of 7) provided: K2O 12.42, SO3 18.04, V2O5 4.30, UO3 61.46, H2O 3.90 (structure), total 100.12 (all in wt%). The empirical formula (based on 33 O atoms pfu) is: K4.87(U0.99O2)4(S1.04O4)4(V0.87O5)(H2O)4. The eight strongest powder X-ray diffraction lines are [dobs in Å (hkl) Irel]: 10.64 (110) 76, 7.486 (200) 9, 6.856 (001) 100, 6.237 (101) 85, 4.742 (310) 37, 3.749 (400) 27, 3.296 (401) 9, and 2.9409 (510) 17. The crystal structure of mathesiusite was solved from single-crystal X-ray diffraction data and refined to R1 = 0.0520 for 795 reflections with I > 3σ(I). It contains topologically unique heteropolyhedral sheets based on [(UO2)4(SO4)4(VO5)]5- clusters. These clusters arise from linkages between corner-sharing quartets of uranyl pentagonal bipyramids, which define a square-shaped void at the center that is occupied by V5+ cations. Each pair of uranyl pentagonal bipyramids shares two vertices of SO4 tetrahedra. Each SO4 shares a third vertex with another cluster to form the sheets. The K+ cations are located between the sheets, together with a single H2O group. The corrugated sheets are stacked perpendicular to c. These heteropolyhedral sheets are similar to those in the structures of synthetic uranyl chromates. Raman spectral data are presented confirming the presence of UO22+, SO4, and molecular H2O. [ABSTRACT FROM AUTHOR]

Two types of V-rich dravitic tourmaline (oxy-dravite to dravite) distinct in their color, morphology, paragenesis and composition from graphite quartzite at Bítovánky near Třebí, Moldanubicum, Bohemian Massif, were studied by means of electron microprobe, laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS), and single-crystal X-ray diffraction. Green oxy-dravite (GVD) from graphite quartzite is sporadically zoned with V-enriched rims; brown oxy-dravite to dravite (BVD) from mobilized quartz-rich nests is characterized by such V-enriched rims. The formulae derived from chemical and structure data of the two oxy-dravite varieties are x(Na0.534 Ca0.284◻0.164K0.018) Y(Mg1.461V0.679Al0.771Fe0.042Mn0.003Ti0.043) Z(Al5.074V0.237Mg0.689) T(Si5.782 Al0.218O18) (BO3)3 [(OH)3.058O0.75F0.192] for GVD and X(Na0.539Ca 0.148◻0.297K0.017) Y(Mg0.992V0.302Al1.039Fe0.532Mn0.001 Ti0.068Cr0.007) Z(Al5.339 V0.082Mg0.578) T(Si5.864 Al0.136) (BO3)3 [(OH)3.209O0.621F0.017] for BVD, respectively. Both types of V-rich oxy-dravite feature Al-Mg-V disorder between the Y and Z sites; V and Cr are preferentially located at the Y site. The V-rich oxy-dravite from Bitovánky has unusually high Ca contents and high proportion of vacancy at the X site. Most common trace elements include Ti, Cr, Mn, Zn, Sc, Ga, Sr, Ni, Sn, and LREE. High concentrations of V, Cr and Ti (as well as elevated Mn, Zn, Sc, Sn, and Sr) in the GVD and late BVD most probably result from hydrothermal dissolution of(Ti,V)-oxides and other accessory phases during a high-grade metamorphic overprinting of the host graphite quartzite assemblage. [ABSTRACT FROM AUTHOR]

A new member of the gadolinite supergroup, gadolinite-(Nd), IMA2016-013, ideally Nd2FeBe2Si2O10, was found in the Malmkärra mine, -3.5 km WSW of Norberg, south-central Sweden, where it occurs in association with fluorbritholite-(Ce), västmanlandite-(Ce), dollaseite-(Ce), bastnäsite-(Ce) and tremolite. Gadolinite-(Nd) forms anhedral grains up to 150 µm in size, commonly occurring as aggregates of olive green colour. The crystals are transparent with vitreous to adamantine lustre. Gadolinite-(Nd) is brittle with conchoidal fracture, no cleavage or parting was observed. It has a white streak, the Mohs hardness is 6.5-7 and the calculated density is 4.86 g cm-3. Optically, the mineral is weakly pleochroic in shades of olive green, biaxial (-), nα = 1.78(1), nβ(calc.) = 1.80, nγ = 1.81(1) measured in white light, 2V(meas.) = 62(3)°. Electron-microprobe and laser ablation inductively coupled plasma mass spectrometry analysis [in wt.%] provided SiO2 21.77, Y2O3 5.49, La2O3 2.78, Ce2O3 14.04, Pr2O3 3.28, Nd2O3 19.27, Sm2O3 5.30, Eu2O3 0.24, Gd2O3 4.10, Tb2O3 0.36, Dy2O3 1.32, Ho2O3 0.18, Er2O3 0.38, MgO 0.51, CaO 0.14, MnO 0.10, FeO 10.62, B2O3 0.10, BeOcalc. 8.99, H2Ocalc. 0.55 and total 99.52 giving the following empirical formula [ABSTRACT FROM AUTHOR]

Babánekite, Cu3(AsO4)2∙8H2O, a new member of the vivianite group was found in material originating from the Geister vein, Rovnost mine, Jáchymov, Western Bohemia, Czech Republic. It occurs as a supergene alteration mineral in association with members of the lindackerite supergroup (veselovskýite, hloušekite, pradetite and lindackerite), lavendulan, gypsum and an X-ray amorphous Cu-Al-Si-O-H phase. Crystals of babánekite are pinkish to peach-colored, elongated, prismatic and up to 2 mm in length. They exhibit the forms {010}, {100}, {110}, {101} and less frequently also {001}. Crystals are transparent to translucent with a vitreous luster. The mineral has a light pinkish streak. Estimated Mohs hardness is between 1.5 and 2. The cleavage is perfect on {010}. The calculated density is 3.192 g/cm3. Electron-microprobe analysis yielded CoO 8.89, NiO 4.06, CuO 15.31, ZnO 10.87, P2O5 0.16, As2O5 39.79, SO3 0.13, H2O 24.78 (calc.), total 103.99 wt.% giving the empirical formula (Cu1.12Zn0.78Co0.69Ni0.32)Σ2.91[(AsO4)2.01(PO4)0.01(SO4)0.01]Σ2.03∙8H2O based on 16 O apfu. The ideal end-member formula of babánekite is Cu3(AsO4)2 ∙8H2O, which requires CuO 38.95, As2O5 37.52, H2O 23.53, total 100.00 wt.%. Babánekite is monoclinic, C2/m, with a = 10.1729(3), b = 13.5088(4), c = 4.7496(1) Å, β = 105.399(2)°, V = 629.28(3) ų and Z = 2. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 7.936(11)(110), 6.743(100)(020), 3.231(14)(13-1), 2.715(11)(041), 2.3331(10)(15-1), 2.0819(5)(350), 1.6862(16)(080) and 1.6107(4)(55-1). The crystal structure of babánekite, refined to R1 = 2.18 % for 864 unique observed reflections, confirmed that the atomic arrangement is similar to other members of the vivianite group of minerals. The mineral is named for Ing. František Babánek (1836-1910), Czech mining and geological expert, who worked in the Jáchymov and Příbram mines. [ABSTRACT FROM AUTHOR]

Línekite, K2Ca3[(UO2)(CO3)3]2.8H2O, is a new uranyl tricarbonate mineral from Jáchymov, Western Bohemia, Czech Republic. It occurs in association with grimselite, andersonite, liebigite, čejkaite, schröckingerite, agricolaite, ježekite and braunerite. Línekite forms from uranium-rich aqueous solutions and its origin is associated with post-mining processes. Línekite is orthorhombic, space group Pnnm, with a = 17.0069(5) Å, b = 18.0273(5) Å, c = 18.3374(5) Å and V = 5622.1(2) Å3, and Z = 8. It forms tabular, mostly isometric crystals, up to c. 0.5 mm across, typically in multiple intergrowths. The color is pale olive to khaki green and it has a greenish white to yellowish white streak. Crystals are transparent and have vitreous luster. The Mohs hardness is estimated to be between 2 and 3. Línekite is brittle with an uneven fracture and perfect cleavage on {100} and very good cleavage on {010}. It exhibits intense greenish yellow luminescence under both short- (254 nm) and long-wave (366 nm) UV radiation. The calculated density is 2.922 g/cm3. The mineral is biaxial (+) with indices of refraction, α = 1.546(2), β = 1.550, γ = 1.562(2). The 2Vobs is moderate; the calculated 2V is +60°. Optical orientation: Y = a, X = b, Z = c. The electron microprobe analyses (average of 28) provided: Na2O 0.06, K2O 6.89, CaO 14.11, CuO 0.12, UO3 48.76, CO2* 22.51, H2O* 12.20 (~12.9 from TG) (*calculated), total 104.65 wt%. The empirical formula (based on 30.22 O apfu) is: (K1.73Na0.02)Ʃ1.75(Ca2.97Cu0.02)Ʃ2.99[(UO2)(CO3)3]2.02(H2O)8.00. The Raman and infrared spectra exhibit prominent features consistent with the mineral being a hydrated uranyl tricarbonate, with fundamental vibrations of H2O molecules, CO3 2- anions and UO2 2+ ions. The seven strongest powder X-ray diffraction lines are [dobs in Å (hkl) Irel]: 8.627 (200) 100, 6.436 (022) 60, 5.935 (212) 11, 5.153 (222) 43, 4.592 (004) 19, 4.505 (040) 12 and 4.053 (204) 15. The structure of línekite was refined from single-crystal X-ray data to R = 0.034 for 4468 unique observed reflections (Iobs > 30I). The structure consists of prominent (Ca(H2O)2[(UO2)(CO3)3])2- layers parallel to (100), which define a square grid, leading to a strong tetragonal pseudosymmetry of línekite. Between the layers, disordered K+ cations and H2O molecules are localized. The structure is closely related to other uranyl tricarbonate minerals, e.g., albrechtschraufite and andersonite, due to the presence of a very characteristic paddle-wheel motif, Ca[(UO2)(CO3)3]4Ca. [ABSTRACT FROM AUTHOR]

Lucchesiite, CaFe32+ Al6(Si6O18)(BO3)3(OH)3O, is a new mineral of the tourmaline supergroup. It occurs in the Ratnapura District, Sri Lanka (6°35'N, 80°35′E), most probably from pegmatites and in Mirošov near Strážek, western Moravia, Czech Republic, (49°27′49.38″N, 16°9′54.34″E) in anatectic pegmatite contaminated by host calc-silicate rock. Crystals are black with a vitreous lustre, conchoidal fracture and grey streak. Lucchesiite has a Mohs hardness of ~7 and a calculated density of 3.209 g/cm3 (Sri Lanka) to 3.243 g/cm3 (Czech Republic). In plane-polarized light, lucchesiite is pleochroic (O = very dark brown and E = light brown) and uniaxial (–). Lucchesiite is rhombohedral, space group R3m, a ≈ 16.00 Å, c ≈ 7.21 Å, V ≈ 1599.9 Å3, Z = 3. The crystal structure of lucchesiite was refined to R1 ≈ 1.5% using ~2000 unique reflections collected with MoKα X-ray intensity data. Crystal-chemical analysis for the Sri Lanka (holotype) and Czech Republic (cotype) samples resulted in the empirical formulae, respectively: X(Ca0.69Na0.30K0.02)Σ1.01 Y (Fe1.442+Mg0.72Al0.48Ti0.334+V0.023+ Mn0.01Zn0.01)Σ3.00 Z(Al4.74Mg1.01Fe0.253+)Σ6.00 [T(Si5.85Al0.15)Σ6.00O18](BO3)3 V(OH)3 W[O0.69F0.24(OH)0.07]Σ1.00 and X(Ca0.49Na0.45□0.05K0.01)Σ1.00 Y(Fe1.142+Fe0.953+ Mg0.42Al0.37Mn0.03Ti0.084+ Zn0.01)Σ3.00 Z(Al5.11Fe0.383+Mg0.52)Σ6.00[T(Si5.88Al0.12)Σ6.00O18] (BO3)3 V[(OH)2.66O0.34]Σ3.00 W(O0.94F0.06)Σ1.00. Lucchesiite is an oxy-species belonging to the calcic group of the tourmaline supergroup. The closest end-member composition of a valid tourmaline species is that of feruvite, to which lucchesiite is ideally related by the heterovalent coupled substitution ZAl3+ + O1O2-↔ZMg2 + + O1(OH)1-. The new mineral was approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA 2015-043). [ABSTRACT FROM AUTHOR]

Svornostite (IMA2014-078), K2Mg[(UO2)(SO4)2]2·8H2O, is a new uranyl sulfate mineral from Jáchymov, Western Bohemia, Czech Republic. The new mineral was found in material originating from the Geschieber vein in the Svornost mine. It occurs as crystalline crusts composed of yellow prismatic crystals on a gangue along with geschieberite, adolfpateraite and gypsum. It is a low-temperature, supergene mineral formed by the post-mining weathering of uraninite. Svornostite is orthorhombic, the space group Pmn21, with the unit-cell parameters a = 12.7850(3), b = 8.2683(4), c = 11.2163(3) Å, V = 1185.68(7) ų and Z = 2. Crystals are long prisms elongated on [001] and flattened on {100}. Crystals exhibit the forms {100}, {010} and {011}, usually forming multiple intergrowths. Svornostite is light yellow and has a very pale yellow streak. It exhibits a strong yellowish-green fluorescence under both long-wave and short-wave UV. It is translucent to transparent with strong vitreous luster. The mineral has a Mohs hardness ~2; it is brittle, with uneven fracture and a perfect cleavage, on {100} and {010}. The calculated density based on the empirical formula is 3.268 g/cm³. The mineral is optically biaxial (+), with α = 1.548(2), β = 1.556(3) and γ = 1.585(2) (measured at 590 nm). The 2V was not measured, calculated value is 56°. Birefringence is 0.037. No dispersion or pleochroism was observed. The optical orientation is Z = c. Chemical analysis (EDS, 6 spots) is K2O 7.93, MgO 3.11, CuO 0.79, SO3 28.13, UO3 48.94, H2O (calc.) 12.53, total 101.43 wt. %, which yields the empirical formula K1.94(Mg0.89Cu0.11)S1.00(U0.99O2)2(S1.01O4)4(H2O)8 (based on 28 O apfu). Prominent features in the Raman spectrum include the O-H stretching vibrations, symmetric stretching vibrations of (UO2)2+ ion, and stretching and bending vibrations of symmetrically non-equivalent SO4 groups. The eight strongest powder X-ray diffraction lines are [dobs Å (Irel.) (hkl)]: 8.279(50)(010), 6.398(100)(200), 5.060(55)(210), 4.645(40)(012), 4.610(38)(211), 3.881(34)(021), 3.318(44)(221), 3.009(44)(213). The crystal structure of svornostite (R = 0.023 for 2745 reflections with Iobs > 3σ[I]) contains infinite uranyl sulfate chains of composition [(UO2)(SO4)2(H2O)]2- parallel to (001). The adjacent chains are linked through the Mg2+-octahedra linked to the apical O atoms of the SO4 groups with the chains and additionally by the K-O bonds and also H-bonds involving H2O molecules. The uranyl sulfate chains are the same as found in the structures of several others uranyl sulfate minerals. [ABSTRACT FROM AUTHOR]