THE COPPS MINE is located in sections 14, 15, and 22, T47N, R43W, in Upper Michigan's westernmost county of Gogebic, and approximately 9.8 kilometers north (N17°E) of Marenisco, the nearest communi...
ABSTRACT Mineral species that contain the decavanadate isopolyanion [V10O28]6–, including its protonated and mixed-valence variants, constitute the pascoite family of minerals. Within the pascoite family, the isostructural minerals pascoite and magnesiopascoite form the pascoite group and the isostructural minerals lasalite and ammoniolasalite form the lasalite group. Rakovanite, which was originally assigned the ideal formula Na3[H3V10O28]·15H2O, is redefined with the ideal formula (NH4)3Na3[V10O28]·12H2O.
Abstract The new mineral uranoclite (IMA2020-074), (UO 2 ) 2 (OH) 2 Cl 2 (H 2 O) 4 , was found in the Blue Lizard mine, San Juan County, Utah, USA, where it occurs as tightly intergrown aggregates of irregular yellow crystals in a secondary assemblage with gypsum. The streak is very pale yellow and the fluorescence is bright green–white under 405 nm ultraviolet light. Crystals are translucent with vitreous lustre. The tenacity is brittle, the Mohs hardness is ~1½, the fracture is irregular. The mineral is soluble in H 2 O and has a calculated density of 4.038 g⋅cm –3 . Electron microprobe analyses provided (UO 2 ) 2 (OH) 2.19 Cl 1.81 (H 2 O) 4 . The six strongest powder X-ray diffraction lines are [ d obs Å( I )( hkl )]: 8.85(38)(002), 5.340(100)(200, 110), 5.051(63)( $\bar{2}$ 02), 4.421(83)(112, 004, 202), 3.781(38)( $\bar{2}$ 12) and 3.586(57)(014, $\bar{2}$ 04). Uranoclite is monoclinic, P 2 1 / n , a = 10.763(8), b = 6.156(8), c = 17.798(8) Å, β = 95.656(15)°, V = 1173.5(18) Å 3 and Z = 4. The structure is the same as that of synthetic (UO 2 ) 2 (OH) 2 Cl 2 (H 2 O) 4 in which the structural unit is a dimer consisting of two pentagonal bipyramids that share an equatorial OH–OH edge. The dimers are linked to one another only by hydrogen bonding. This is the second known uranyl mineral containing essential Cl and the first in which Cl coordinates to U 6+ .
ABSTRACT Redcanyonite (IMA2016-082), (NH 4 ) 2 Mn[(UO 2 ) 4 O 4 (SO 4 ) 2 ](H 2 O) 4 , occurs underground in the Blue Lizard mine, Red Canyon, White Canyon district, San Juan County, Utah, USA. It occurs with natrozippeite, brochantite, devilline, posnjakite, johannite, gypsum, bobcookite, pickeringite, pentahydrite and the NH 4 -analogue of zippeite: ammoniozippeite. Redcanyonite occurs as radial aggregates of red–orange needles and blades individually reaching up to 0.2 mm long, with aggregates measuring up to 1 mm in diameter. Crystals are flattened on {010} and elongated along [100], exhibit perfect cleavage on {010}, and exhibit the forms {010}, {001}, {101} and {10 $\bar{1}$ }. Twinning is ubiquitous, by 180° rotation on [100]. Redcanyonite is translucent with a pale orange streak, is non-fluorescent, has a Mohs hardness of 2, and has brittle tenacity with uneven fracture. Optically, redcanyonite is biaxial (+), α = 1.725(3), β = 1.755(3), γ = 1.850(5) (white light); 2V (meas.) = 60(2)°, 2V (calc.) = 61.3°; and dispersion is r < v , very strong. Pleochroism is: X = orange, Y = yellow and Z = orange; Y << X < Z . The optical orientation is X = b , Y ≈ c *, Z ≈ a . The empirical formula is (NH 4 ) 2.02 (Mn 0.49 Cu 0.09 Zn 0.06 ) Σ0.64 H + 0.72 [(UO 2 ) 4 O 4 (S 0.99 P 0.01 O 4 ) 2 ](H 2 O) 4 , based on 4 U and 24 O apfu. Redcanyonite is monoclinic, C 2 /m , a = 8.6572(17), b = 14.155(3), c = 8.8430(19) Å, β = 104.117(18)°, V = 1050.9(4) Å 3 and Z = 2. The structure was refined to R 1 = 0.0382 for 1079 reflections with I obs > 3σ I . Uranyl oxo-sulfate sheets in redcanyonite adopt the well-known zippeite topology, which consists of zigzag chains of uranyl pentagonal bipyramids linked by sulfate tetrahedra to form sheets. The sheets are linked to each other through bonds to interlayer NH 4 + groups and octahedrally coordinated Mn 2+ , and by hydrogen bonds from H 2 O groups. Redcanyonite is named for Red Canyon in southeast Utah, USA.
Abstract The new mineral lussierite (IMA2018-101), Na 10 [(UO 2 )(SO 4 ) 4 ](SO 4 ) 2 (H 2 O) 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 H 2 O 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); 2V meas. = 88(1)°; dispersion is r > v , moderate; pleochroism: X = colourless, Y and Z = green yellow ( X < Y ≈ Z ); optical orientation: X = b , Z ∧ a = 44° in obtuse β. Electron microprobe analyses (wavelength-dispersive spectroscopy mode) provided Na 10 (U 0.99 O 2 )(S 1.00 O 4 ) 6 ·3H 2 O (+0.06 H for charge balance). The five strongest X-ray powder diffraction lines are [ d obs Å( 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) Å 3 and Z = 4. The structure ( R 1 = 0.0298 for 5202 I > 2σ I ) contains a [(UO 2 )(SO 4 ) 4 ] 6– uranyl sulfate cluster in which one SO 4 tetrahedron shares an edge (bidentate linkage) with the UO 7 pentagonal bipyramid. The uranyl sulfate clusters occur in layers and are linked through a complex network of bonds involving Na + cations, isolated SO 4 tetrahedra and isolated H 2 O groups.
Abstract This issue of New Mineral Names provides a summary of the newly described minerals from May to August 2024, including karlseifertite, vegrandisite, touretite, auropolybasite, cuprozheshengite, calcioveatchite, and jianmuite.
The phase Na 5 FeSi 4 O 12 [pentasodium iron(III) silicate] crystallizes readily from the Na 2 O–Fe 2 O 3 –SiO 2 glass system in a relatively large compositional range. However, its crystal structure and properties have not been studied in detail since its discovery in 1930. In this work, the Na 5 FeSi 4 O 12 phase was crystallized from a host glass with 5Na 2 O·Fe 2 O 3 ·8SiO 2 stoichiometry, and both the glass and the crystal were studied. It was found that the Na 5 FeSi 4 O 12 phase crystallizes at ∼720 °C from the glass and melts at ∼830 °C when heated at a rate of 10 °C min −1 . The crystal structure was solved using single-crystal X-ray diffraction and the refined data are reported for the first time for the Na 5 FeSi 4 O 12 phase. It exhibits trigonal symmetry, space group R \overline{3} c , with a = 21.418 and c = 12.2911 Å. The Na atoms located between adjacent structural channels exhibit positional disorder and splitting which was only refined by using low-temperature data collection (150 K). While ∼7% of the total Fe cations occur as Fe 2+ in the glass, four-coordinated Fe 3+ constitutes ∼93% of the total Fe cations. However, iron in the crystal, which exhibits a paramagnetic behavior, is solely present as six-coordinated Fe 3+ . The magnetic and vibrational properties of the glass and crystal are discussed to provide additional insight into the structure.
Abstract Trebiskyite, Na3Mg2[TiV9O28]·22H2O, from the Pickett Corral mine, Bull Canyon, Montrose County, Colorado, USA, is the first mineral containing essential Ti as a component of a decavanadate polyanion. Crystals are thin prisms or needles up to ∼0.3 mm in length, occurring as individuals and in divergent sprays. Trebiskyite crystals are translucent yellow with vitreous luster and pale-yellow streak and are non-fluorescent under both longwave and shortwave ultraviolet illumination. The crystals exhibit elongation on [001] and are modified by several 0kl prism forms, possibly corresponding to {010}, {011}, and {012}. The Mohs hardness is ca. 2 based on scratch tests. Crystals have brittle tenacity with irregular fracture. No apparent cleavage, nor twinning, was evident, and the mineral is readily soluble in H2O. The density measured by flotation in methylene iodide-toluene mixture is 2.38(2) g/cm3. The calculated density is 2.352 g/cm3 for the empirical formula and 2.343 g/cm3 for the ideal formula. Electron microprobe analyses provided the empirical formula Na3.39Mg1.87V8.75Ti1.25O50H44.00, based on Ti + V = 10 apfu, O = 50 apfu, with the Na content having been determined from the refined crystal structure. Trebiskyite is monoclinic, space group P21/c, a = 9.478(4), b = 21.426(11), c = 11.267(5) Å, β = 114.572(7)°, V = 2080.8(13) Å3, Z = 2. The structure was refined from 6642 reflections to a final R1 = 0.0517 for reflections I > 2σ(I). The structural unit of trebiskyite, (TiV9O28)7−, is built from a Ti-substituted decavanadate polyanion, (V10O28)6−, found in other members of the pascoite family. Chemically, trebiskyite is closely related to lasalite, Na2Mg2[V10O28]·20H2O, and huemulite, Na4Mg[V10O28]·24H2O; however, trebiskyite contains a novel structural arrangement that is unique among the decavanadate minerals. The interstitial complex in trebiskyite has the ideal formula {[Na3Mg2(H2O)19](H2O)3} and consists of chains of distorted octahedrally coordinated Na+ and regular Mg[O(H2O)5] octahedra. The observed low incident bond valence to the V1 site (4.45 vu) and marked deviation in vanadyl and V–Oeq bond lengths indicate that this site is host to the essential Ti4+ identified during chemical analyses.
