Čejkaite, the triclinic polymorph of Na4(UO2)(CO3)3—a new mineral from Jáchymov, Czech Republic (original) (raw)
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Mineralogical Magazine, 2013
Fluorcalcioroméite, (Ca,Na)2Sb25+(O,OH)6F, is a new roméite-group, pyrochlore-supergroup mineral (IMA 2012-093), from Starlera mine, Ferrera, Hinterrhein district, Grischun, Switzerland. The intimately associated minerals are: braunite, hematite, calcite, quartz and, rarely, wallkilldellite-(Mn). It occurs as euhedral octahedra, untwinned, from 0.1 to 1 mm in size. The crystals are yellow to orange and translucent; the streak is white, and the lustre is vitreous to resinous. It is non-fluorescent under ultraviolet light. Mohs' hardness is ∼5½, tenacity is brittle. Cleavage is not observed; fracture is conchoidal. The calculated density is 5.113 g/cm3. The mineral is isotropic, ncalc. = 1.826. The Raman spectrum is dominated by bands of Sb–O octahedral bond stretching and O–Sb–O bending modes. The chemical composition (n = 13) is (by wavelength-dispersive spectroscopy (WDS), H2O calculated by difference, wt.%): Na2O 4.11, CaO 15.41, MnO 0.54, CuO 0.01, ZnO 0.01, PbO 0.02, Al2O3 0...
Biraite-(Ce), Ce2Fe2+(CO3)(Si2O7), a new mineral from Siberia with a novel structure type
European Journal of Mineralogy, 2005
The new mineral, which is being herewith described, was sampled in the Biraia deposit (Irkutsk district, Russia). On the basis of its appearance and preliminary qualitative chemical data, it was thought to be the iron-dominant analogue of törnebohmite. Whereas such a close relation with törnebohmite was soon ruled out after the singlecrystal X-ray diffraction study of the unknown phase, we still believed that it could be a possible new REE-and Febearing silicate mineral. A complete structural investigation revealed the unique crystal-chemical nature of the unknown mineral, which is characterized by the unex-pected presence of both disilicate and carbonate groups, and by the ideal formula Ce 2 Fe 2+ (CO 3 )(Si 2 O 7 ). Therefore, a complete set of descriptive data was collected for the definition of the new mineral species, and it was submitted to the IMA Commission on New Minerals and Mineral Names. The mineral (proposal # 2003-037) has been approved with the name biraite-(Ce), which was chosen after the type locality (Biraia is the name of both the deposit and the river in the Irkutsk district), plus the Levinson modifier for the dominating REE. The type material is deposited at the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow (collection No. 91375).
A monoclinic K-Li-Cu-Mg silicate from the Cerchiara mine: a dimorph of lavinskyite?
2014
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Geology of Ore Deposits, 2007
family were described for the first time only 40 years ago after the discovery of magadiite and kenyaite in the soda-bearing sediments of Lake Magadi, Kenya . A few years later, makatite and kanemite also found in the sediments of African soda lakes were described by and . Other findings in a similar environment showed that hydrous sodium silicates are characteristic of alkali carbonate supergene, foremost, the sedex-type mineral assemblages. Subsequently, the members of this family were described from a quite different setting. Makatite and new minerals-revdite and grumantite-were found in the salt mineralization of the late, low-temperature derivates of hyperalkaline igneous rocks in the Lovozero alkaline pluton, Kola Peninsula, Russia (Khomyakov et al.
Ktenasite, another mineral with∞2[(Cu,Zn)2(OH)3O]−octahedral sheets
Zeitschrift für Kristallographie, 1978
The crystal structure of ktenasite from Miniera Trentin (space group P2i/c, α = 5.589, b = 6.166, c = 23.751 Á, β = 95.55°) was determined by Patterson and Fourier methods and refined to a final R value of 0.058. The structure is characterized by corrugated sheets ^[(Cu.ZnMOHJaO]-of distorted copper-zinc polyhedra. Sulphate groups are connected to both sides of the octahedral sheet by corner sharing. The resultant composite tetrahedraloctahedral layers are connected each other by [Ζη(Η2θ)β] +2 octahedra through a system of hydrogen bonds. The crystal chemical formula for ktenasite from Miniera Trentin is Zn2(Cu5.2Zn2.8)(S04)4(0H)i2 • 12H20. The relations of ktenasite with other minerals are remarked and discussed.
Felbertalite, Cu2Pb6Bi8S19, a new mineral species from Felbertal, Salzburg Province, Austria
European Journal of Mineralogy, 2001
Felbertalite, a new copper-lead-bismuth-sulphosalt, has been found in quartz veins, in the scheelite deposit Felbertal, Salzburg Province, Austria. It occurs as rare elongated crystals, up to 0.5 mm long and 0.2 mm in diameter. The mineral is always in contact with Ag-bearing lillianite and a Se-free junoite-like mineral. Associated minerals are: cosalite, galenobismutite, members of the bismuthinite-aikinite series, galena, native Bi and traces of chalcopyrite. Felbertalite is opaque, with metallic lustre and greyish-black streak. In reflected light, it has a white colour with distinct anisotropy and perceptible bireflectance in air and oil and without internal reflections. Reflectance data and colour values are supplied. Mohs hardness is 3.3-3.4, according to a microhardness VHN 25 of 197-216 kg/mm 2 . The mean of 15 electron-microprobe analyses is: Cu 3.56, Ag 1.02, Pb 30.10, Cd 0.38, Bi 48.3, Te 0.23, S 16.76, total 100.36 wt.%, from which a simplified formula Cu 2 Pb 6 Bi 8 S 19 (on the basis of 35 atoms) can be derived. The mineral has a monoclinic unit cell with a = 27.637(4), b = 4.0499(6), c = 20.741(3) Å, = 131.258(2) o , V = 1745.1(7) Å 3 , a:b:c = 6.82:1:5.12, Z = 2, space group C2/m. The calculated density is D calc = 6.948 g/cm 3 . The strongest five lines in the X-ray powder pattern [d in Å, (I), (hkl)] are: 2.904
American Mineralogist, 2016
Two new uranyl sulfates, geschieberite (IMA 2014-006), ideally K 2 (UO 2)(SO 4) 2 (H 2 O) 2 and svornostite (IMA 2014-078), ideally K 2 Mg[(UO 2)(SO 4) 2 ] 2 •(H 2 O) 8 were recently discovered in the Geschieber vein at the Svornost mine, Jáchymov (Joachimsthal), Western Bohemia, Czech Republic, and named for their type locality. The Jáchymov ore district is a classic example of the Variscan hydrothermal vein type of deposit, so-called five-element formation, Ag-Bi-Co-Ni-U. Both new minerals are the supergene products of the post mining alteration of the uraninite and sulfides of the primary ore. They occur in the close association with each another and with adolfpateraite, gypsum and mathesiusite. Both minerals exhibit strong yellowish green fluorescence under both short-and long-wave UV radiation. Both are brittle, have an uneven fracture, and estimated Mohs hardness of ~2. Both are unstable under electron beam so the EDS mode was chosen for electron probe measurements. Geschieberite forms bright green, compact crystalline aggregates composed of multiple intergrowths of prismatic {010} crystals elongated on [001] typically 0.1-0.2 mm across sometimes modified by {001}. The crystals are translucent pale green with greenish-white streak and a vitreous luster. The cleavage is perfect on {100}. The density could not be measured due to paucity of pure material; D calc = 3.259 g/cm 3. Geschieberite is slightly soluble in cold H 2 O. It is optically biaxial (-), β = 1.596(2), γ = 1.634(4) (590 nm); X = a. In a plane-polarized transmitted light, the mineral is nearly colorless with no apparent pleochroism. The average of 7 electron probe EDS analyses is [wt% (range)]: Na 2 O 0.23 (0.12-0.59), K 2 O 14.29 (12.90-16.66), MgO 2.05 (1.77-2.52), CaO 0.06 (0-0.12), UO 3 49.51 (47.23-51.64), SO 3 27.74 (26.82-28.78), H 2 O 6.36 (by structure refinement), total 100.24. This gives the empirical formula (K 1.72 Mg 0.29 Na 0.04 Ca 0.01) Σ2.06 (U 0.98 O 2)(S 0.98 O 4) 2 (H 2 O) 2 based on 12 O apfu. The strongest lines in the X-ray powder-diffraction pattern [d Å (I%; hkl)]