Nisnite, ideally Ni 3 Sn, was found during a re-examination of heazlewoodite crystals in rodingite samples from the Jeffrey mine, Asbestos, Quebec. It occurs as bronze-colored metallic, striated, blocky and square to rectangular tabular crystals of up to 100 μm in length, with groupings of ≤1 mm growing on heazlewoodite. Crystal groupings exhibit a boxwork-like habit. Reflectance measurements in air gave 43.2 (470 nm), 49.1 (546 nm), 53.2 (589 nm), and 59.0% (650 nm). Minerals closely associated with nisnite are chromite, diopside, grossular, heazlewoodite and shandite. The mineral is cubic, P 4/ m 32/ m , with unit-cell parameter refined using powder-diffraction data: a 3.7349(6) A, V 52.10(3) A 3 , Z = 1, D calc = 9.41 g/cm 3 . The average results of five and three electron-microprobe analyses on separate crystals gave Ni 57.88, Sn 40.17, sum 98.05 wt.% and Ni 59.24, Sn 41.00, sum 100.24 wt.%, corresponding to Ni 2.98 Sn 1.02 on the basis of 4 apfu . The structure has been refined to an R index of 0.008% on the basis of 30 unique reflections. The structure of nisnite contains 12-coordinated Sn atoms (12 Ni) and 12-coordinated Ni atoms (8 Ni and 4 Sn). Among the three synthetic Ni 3 Sn phases known, nisnite corresponds to the ccp structure that has been synthesized at high pressure and high temperature.
Bussyite-(Ce), ideally (Ce,REE,Ca) 3 (Na,H 2 O) 6 MnSi 9 Be 5 (O,OH) 30 (F,OH) 4 , a new mineral species, was found in the Mont Saint-Hilaire quarry, Quebec. The crystals are transparent to translucent, pale pinkish orange in color, with a white streak and vitreous luster. Bladed crystals are prismatic, having forms {111} and {101}; they are elongate on [101], up to 10 mm in length. Associated minerals include aegirine, albite, analcime, ancylite-(Ce), calcite, catapleiite, gonnardite, hydrotalcite, kupletskite, leucophanite, microcline, nenadkevichite, polylithionite, serandite and sphalerite. Bussyite-(Ce) is monoclinic, space group C 2/ c , with unit-cell parameters refined from powder-diffraction data: a 11.654(3), b 13.916(3), c 16.583(4) A, β 95.86(2)°, V 2675.4(8) A 3 and Z = 4. Electron-microprobe and secondary-ion mass spectrometric analyses give the average and ranges: Na 2 O 7.63 (9.40–6.62), K 2 O 0.05 (0.13–0.0), BeO 8.33 (SIMS), CaO 5.35 (5.95–4.17), MgO 0.03 (0.11–0.00), MnO 2.49 (3.00–1.71), Al 2 O 3 0.82 (1.54–0.39), Y 2 O 3 1.97 (2.68–1.51), La 2 O 3 2.65 (3.11–2.16), Ce 2 O 3 9.77 (11.22–8.15), Pr 2 O 3 1.23 (1.49–0.74), Nd 2 O 3 4.54 (5.13–3.91), Sm 2 O 3 0.99 (1.25–0.68), Eu 2 O 3 0.010 (0.25–0.0), Gd 2 O 3 1.03 (1.23–0.81), SiO 2 38.66 (39.94–37.66), ThO 2 3.31 (4.59–2.12), F 3.67 (6.39–2.54), S 0.03 (0.08–0), H 2 O 4.12 (determined from crystal-structure analysis), for a total of 95.21 wt.%. The empirical formula based on the crystal-structure analysis, ideally showing 34 anions, is: 4{(Ce 0.823 Nd 0.373 Y 0.242 Th 0.173 Pr 0.103 Sm 0.079 Gd 0.078 Eu 0.008 ) ∑1.879 (Ca 0.775 La 0.225 ) ∑1 [Na 3.000 (H 2 O) ∑2.500 Ca 0.544 K 0.015 ] ∑6.055 (Mn 0.485 Na 0.402 Mg 0.012 ) ∑0.899 (Si 8.897 Be 4.605 Al 0.222 ) ∑13.724 O 30 [F 2.67 (OH) 1.33 ] ∑4 }. The structure has been refined to an R index of 4.0% for 1134 unique, observed reflections. The structure has two chemically distinct layers parallel to (101): (1) a layer of [(Si,Be)O 4 ] tetrahedra, and (2) a layer of Ce–, Ca–, Mn–, Na–(O,F) polyhedra. Layers are cross-linked through shared O and F atoms. Significant amounts of OH and H 2 O are present, as indicated in the IR spectrum and crystal-structure analysis for the Na-poor hydrated phase. One instance of a rarer Na-rich phase is observed. Based on the electron-microprobe data, the formula for the rarer Na-rich anhydrous phase is 4{(Ce 1.047 Nd 0.466 La 0.323 Y 0.306 Pr 0.131 Sm 0.102 Gd 0.084 Eu 0.009 Th 0.042 ) ∑2.510 (Na 6.645 Ca 0.701 ) ∑7.346 (Si 9.521 Be 4.772 ) ∑14.293 O 29.251 F 4.749 }. Comparing the structure of bussyite-(Ce) to that of other beryllium silicates, the topology of the layer of tetrahedra most strongly resembles that of semenovite-(Ce) and the closely related mineral harstigite.
Eldragonite, with the simplified formula Cu 6 BiSe 4 (Se 2 ), is a new mineral species discovered in a telethermal vein-type deposit with selenides at the El Dragon mine, Province of Quijarro, Department of Potosi, Bolivia. It forms inclusions in krut’aite, and is associated with clausthalite, klockmannite, umangite and tiemannite, as well as with watkinsonite, petrovicite and two unnamed phases in the system Cu–Pb–Hg–Bi–Se. The unique vein of eldragonite-bearing krut’aite is hosted within sandstones and shales of Devonian age. Eldragonite occurs in anhedral grains and polycrystalline aggregates attaining a size of up to 100 × 80 μm. Megascopically, the mineral has a brownish to light-maroon color, is opaque and lacks internal reflections. It has a metallic luster and a brownish black streak, is brittle with an uneven to conchoidal fracture, without observable cleavage. The VHN 15 values range between 212 and 243 (mean 225) kg/mm 2 , corresponding to a Mohs hardness of ~3 ½. In plane-polarized light, eldragonite is distinctly bireflectant and pleochroic, from light grayish brown to cream; it is strongly anisotropic with rotation tints in shades of orange and blue-black. The reflectances (in air and oil, respectively) for the COM standard wavelengths are: 32.5–34.5, 17.7–19.7 (470 nm), 32.95–36.3, 18.0–21.4 (546 nm), 33.3–36.8, 18.3–21.6 (589 nm), 34.0–36.9, 19.1–21.7 (650 nm). Electron-microprobe analyses gave (mean of 24 analyses): Cu 35.9, Fe 1.25, Ni 0.35, Bi 20.3, Se 42.5, total 100.3 wt.%, corresponding to (Cu 5.98 Fe 0.24 Ni 0.06 ) ∑6.28 Bi 1.03 Se 5.70 . The ideal formula is Cu 6 BiSe 4 (Se 2 ), which requires Cu 35.84, Bi 19.64, Se 44.52 wt.%. Eldragonite has an orthorhombic cell, space group Pmcn , with a 4.0341(4), b 27.056(3), c 9.5559(9) A, V 1043.0(3) A 3 , and Z = 4. The calculated density is 6.76 g/cm 3 . The strongest X-ray powder-diffraction lines [ d in A ( I ) hkl ] are: 6.547(58)031, 3.579(100)052, 3.253(48)141, 3.180(77)081, 3.165(56)013, 3.075(84)102, 3.065(75)151,112, 2.011(53)200, 1.920(76)154, 1.846(52)1103. The crystal structure was solved from single-crystal data, and was refined to R 1 = 0.026 on the basis of 1731 unique reflections. There are one Bi and six Cu positions. Among the six Se positions, two Se atoms form a Se 2 pair [d(Se–Se) = 2.413 A]; eldragonite is thus a mixed selenide–diselenide compound. The crystal structure is organized according to two slabs alternating along a . The thin slab with formula Cu 6 Se 6 is a zigzag layer derived from the CaF 2 archetype; the thick slab, Cu 6 Bi 2 Se 6 , is similar to that of wittichenite, Cu 3 BiS 3 . The Se 2 pair is at the junction between these two slabs. This new mineral species is named after the location where it was discovered.
La qaqarssukite-(Ce), de formule ideale BaCe(CO 3 ) 2 F, est une espece minerale recemment decouverte dans le complexe carbonatitique de Qaqarssuk, dans le secteur sud du Groenland occidental. Elle se presente en cristaux isoles jaunâtres ou bruns ou en amas. Les cristaux atteignent 50 μm, et les aggregats, 2 mm de diametre. Ce mineral serait une composante importante du minerai potentiel a cet endroit. Lui sont associes calcite, dolomite, strontianite, phlogopite et pyrite. Le mineral possede un eclat subadamantin a gras, et une rayure blanche. Il est relativement mou (durete de Mohs de 3 a 4) et cassant, avec une fracture inegale. La qaqarssukite-(Ce) est uniaxe positive, w 1.672(3), e 1.751(5), et non pleochroique. Elle est trigonale, groupe spatial P3cl, avec les parametres reticulaires suivants, affines a partir de donnees en diffraction X, methode des poudres: a 7.2036(9), c 18.172(3) A, V 816.6(2) A 3 et Z = 6. Les huit raies les plus intenses du spectre de diffraction [d en A(I)(hkl)] sont: 5.14(28)(102), 4.55(43)(004), 3.671(32)(104), 3.534(41)(111), 3.348(100)(112), 3.093(40)(113), 2.569(35)(204) et 2.078(60)(300). Les analyses obtenues avec une microsonde electronique et une ebauche de la structure cristalline ont donne: CaO 2.82, SrO 3.92, BaO 27.41, La 2 O 3 8.82, Ce 2 O 3 20.26, Pr 2 O 3 1.85, Nd 2 O 1 6.64, Sm 2 O 3 0.37, Eu 2 O 3 0.18, TiO 2 1.41, P 2 O 5 0.05, F 5.04, CO 2 (23.00), O = F -2.12, pour un total de 99.65% (poids). La formule empirique, fondee sur sept anions et deux groupes [CO 3 ], est (Ba 0.68 Ca 0.19 Sr 0.14 ) Σ1.01 (Ce 0.47 Lar 0.21 Nd 0.15 Pr 0.04 Sm 0.01 Ti 0.07 ) Σ0.95 (CO 3 ) 2 F 1.01 . La densite calculee a partir de la formule empirique est 4.64 g/cm 3 . La structure a ete affinee jusqu'a un residu R de 0.111. Elle contient trois couches chimiquement distinctes paralleles a (001):(1) des groupes de carbonate orientes perpendiculairement aux couches, (2) un niveau de polyedres a Ce-O-F, et (3) un niveau de polyedres a Ba-O-F. La qaqarssukite-(Ce) possede une relation polymorphique avec la huanghoite-(Ce), mais sa structure cristalline ressemble a celle de la synchysite-(Ce). Le nom rappelle la localite-type.
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