The Cu0.8Mg1.2Si2O6 pyroxene has been synthesized using a soft chemistry method. Its crystal structure was determined from powder X-ray diffraction data. Cu0.8Mg1.2Si2O6 crystallizes with the lowclinopyroxene monoclinic structure (space group P21/c). The role of the Jahn-Teller-distorted Cu2+ cation on the stability of this strongly distorted structure is investigated. Cu2+ shows a strong preference for the M2 site, attributed to a better adaptation of its JT-distorted coordination polyhedron to this already distorted and more flexible site. Comparison with previously reported compounds indicates that increasing the Cu content enhances the M2 site distortion, eventually leading to symmetry lowering from orthorhombic Pbca to monoclinic P21/c. These observations bring new insight into the mechanisms of formation and chemical composition of pyroxene minerals in the presence of JT cations.

The new mineral species ferrostalderite, CuFe2TlAs2S6, was discovered in the Lengenbach quarry, Binn Valley, Wallis, Switzerland. It occurs as minute, metallic, black, equant to prismatic crystals, up to 50 mu;m, associated with dolomite, realgar, baumhauerite (?) and pyrite. Minimum and maximum reflectance data for COM wavelengths in air are [λ (nm): R (%)]: 471.1: 24.2/25.4; 548.3: 23.7/24.7; 586.6: 22.9/23.8; 652.3: 21.0/22.0. Electron microprobe analyses give (wt.%): Cu 6.24(25), Ag 4.18(9), Fe 9.95(83), Zn 4.46(91), Hg 1.22(26), Tl 26.86(62), As 19.05(18), Sb 0.63(6),S 25.39(47), total 97.98(72). On the basis of 12 atoms per formula unit, the chemical formula of ferrostalderite is Cu0.75(2)Ag0.30(1)Fe1.36(10) Zn0.52(11) Hg0.05(1) Tl1.00(1)[As1.94(4)Sb0.04(1)]∑1.98(4)S6.04(4). The new mineral is tetragonal, space group I4̄2 m, with a = 9.8786(5), c = 10.8489(8) Å, V = 1058.71(11) Å3, Z = 4. The main diffraction lines of the calculated powder diagram are [d (in Å), intensity, hkl]: 4.092, 70, 211; 3.493, 23, 220; 3.396, 35, 103; 3.124, 17, 310; 2.937, 100, 222; 2.656, 19, 321; 2.470, 19, 400; 2.435, 33, 303. The crystal structure of ferrostalderite has been refined by Xray single-crystal data to a final R1 = 0.050, on the basis of 1169 reflections with F0 > 4σ(F0). It shows a three dimensional framework of (Cu,Fe)-centred tetrahedra (1M1 + 2 M2), with channels parallel to [001] hosting disymmetric TlS6 and (As,Sb)S3 polyhedra. Ferrostalderite is derived from its isotype stalderite M1CuM2Zn2TlAs2S6 through the homovalent substitution M2Zn2+ → M2Fe2+. The ideal crystal-chemical formula of ferrostalderite is M1CuM2Fe2TlAs2S6.

A new tsumcorite-group mineral, nickeltsumcorite, Pb(Ni,Fe3+)2(AsO4)2(H2O,OH)2, the Ni-dominant analogue of tsumcorite and cobalttsumcorite, was found in the oxidation zone of a hydrothermal orebody containing gersdorffite and galena at the Km-3 mine, Lavrion, Attikí Prefecture, Greece. It is associated with annabergite, nickellotharmeyerite, nickelaustinite, gaspéite, calcite, dolomite, aragonite, quartz, goethite, cerussite, arseniosiderite, mimetite, oxyplumboroméite and Mn oxides/hydroxides. Nickeltsumcorite occurs as open-work aggregates and interrupted crusts up to 3 mm × 5 mm in area and up to 0.2 mm thick. They typically consist of coarse radial spherulites or dense concentric nodules up to 0.15 mm in diameter. Bunches or hemispherical clusters of crude individuals and separate imperfect, elongated crystals (up to 0.02 mm long) are also observed. Nickeltsumcorite is yellow, brownish-yellow, light brown or brown, with a yellow streak and a vitreous lustre. The Mohs hardness is ∼4. The mineral is brittle; one direction of distinct cleavage is observed under the microscope. D(calc.) = 5.02 g cm–3. Nickeltsumcorite is optically biaxial (–), α = 1.82(2), β = 1.87(1), γ = 1.90(1), 2V(obs.) is large. The chemical composition (wt.%, electron-microprobe data, H2O by difference) is CaO 2.79, PbO 28.12, MgO 0.30, CoO 0.15, NiO 17.39, ZnO 0.76, Mn2O3 0.57, Fe2O3 6.83, As2O5 38.17, H2O 4.92, total 100.00. The empirical formula, calculated based on 10 O apfu, is (Pb0.76Ca0.30)∑1.06(Ni1.39Fe3+0.51Zn0.06Mn3+0.04 Mg0.04Co0.01)∑2.05As1.99O7.97[(H2O)1.25(OH)0.78]. The strongest reflections in the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 4.64 (100) (1̄11), 4.47 (41)(2̄01), 3.238 (82)(1̄12), 3.008(60)(201), 2.859(41)(021), 2.545(79)(3̄12, 112), 2.545 (79)(3̄12, 112) and 2.505 (61)(220, 2̄03). The cation composition, powder Xray diffraction data and IR spectrum show that nickeltsumcorite belongs to the tsumcorite structure type. The new mineral is monoclinic, space group C2/m, a = 9.124(8), b = 6.339(3), c = 7.567(7) Å, β = 115.19(6)°, V = 396.0(7) Å3 and Z = 2. Nickeltsumcorite forms a solid-solution series with nickellotharmeyerite.

The Neoproterozoic, epidote-bearing Mons Claudianus Batholith (MCB), Egypt, consists of tonalite-trondhjemite-granodiorite (TTG) lithologies, containing variable contents of quartz, feldspars, amphiboles, biotite, and magmatic epidote, with accessory titanite, zircon, allanite, apatite, opaque magnetite and ilmenite. Plagioclase varies from An49 to An19, and K-feldspars possess near end-member compositions (Or97 to Or91). Amphiboles are calcic (Ca = 1.88–1.92 atoms per formula unit (apfu)), Al-rich (average AlT = 1.84 apfu), having an average Fe/(Fe + Mg) ratio of 0.50, and are edenite, ferro-edenite and ferropargasite. The Al-in-Hb barometer produced an average crystallization pressure of 5.5 kbar, consistent with the presence of magmatic epidote; the association epidote – Al-rich-Hb suggests mesozonal crustal levels, and thus a possible average rate of regional uplift for the Nubian Shield would have been in the order of 0.03 mm/yr. Calculated temperatures (using the Hb-Plag geothermometer) range from 729 to 754°C (average 747°C). The calculated P / T values of epidote-bearing MCB rocks fall within the experimentally-determined P-T range of stability of magmatic epidote with fO2 buffered from NNO to HM. Biotites in the MCB are moderately Mg-rich (Fe/(Fe + Mg) = 0.42 to 0.50), and are type 'C'-biotite, typical of calcalkaline orogenic suites, which are distinct from types 'A' and 'P' biotites occurring in anorogenic alkaline, and peraluminous lithologies, respectively. The minor secondary chlorite phases, with their Fe/(Fe + Mg) ratios of 0.37–0.52, are pycnochlorite and ripidolites, and belong to group 'c' chlorites. Minerals of the MCB reflect a petrogenetic history involving a wet, subsolvus, typically orogenic magmatic system. Results of this study could have wide implications for mineralogical characterization, level of emplacement and evolution of magmatic systems of TTG suites occurring in other orogenic belts.

Petrographic and mineralogical studies of samples of the Normal (or undisturbed) Merensky Reef from Frank Shaft No.1 at Rustenburg Platinum Mine revealed the presence of a Pt-Fe-alloy, probably isoferroplatinum (58 vol.% of total precious metal minerals), arsenides (21 vol.%), bismuthotellurides (10 vol.%), electrum (9 vol.%) and platinum group element- (PGE-) sulfides and stannides (2 vol.%), associated predominantly with base-metal- and iron-sulfides. A Pt-Fe-alloy-dominated facies has been known for considerable time from potholes and discordant bodies and has been attributed to fluid activity with high fO2 and low fS2. Our petrographic results indicate that the normal thin reef has also undergone hydrothermal alteration. For the first time, the rare mineral troilite (stoichiometric FeS) was found as intergrowths with masses of Pt-Fe-alloy, together with Fe-rich pyrrhotite, secondary hydrous silicates, magnetite and calcite. The observed mineral assemblage and texture is interpreted as the product of partial desulfurization, caused by migrating S-undersaturated fluids, which led to the exsolution of Pt-Fe-alloy from pyrrhotite (Fex–1S) with the latter approaching a stoichiometric composition. Overall our new observations provide convincing support for the importance of metasomatism in the secondary modification of ore mineralogy and textures even in the undisturbed Merensky Reef.

The new mineral melanarsite, K3Cu7Fe3+O4(AsO4)4, was found in the sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka Peninsula, Russia. It is associated with dmisokolovite, shchurovskyite, bradaczekite, hematite, tenorite, aphthitalite, johillerite, arsmirandite, As-bearing orthoclase, hatertite, pharmazincite, etc. Melanarsite occurs as tabular to prismatic crystals up to 0.4 mm, separate or combined in clusters up to 1 mm across or in interrupted crusts up to 0.02 cm × 1 cm × 1 cm covering basalt scoria. The mineral is opaque, black, with a vitreous lustre. Melanarsite is brittle. Mohs' hardness is ∼4 and the mean VHN = 203 kg mm–2. Cleavage was not observed and the fracture is uneven. D calc is 4.39 g cm–3. In reflected light, melanarsite is dark grey. Bireflectance is weak, anisotropism is very weak. Reflectance values [R1–R2, % (λ, nm)] are 10.5–9.4 (470), 10.0–8.9 (546), 9.7–8.7 (589), 9.5–8.6 (650). The Raman spectrum is reported. Chemical composition (wt.%, electron microprobe) is K2O 10.70, CaO 0.03, CuO 45.11, ZnO 0.24, Al2O3 0.32, Fe2O3 6.11, TiO2 0.12, P2O5 0.07, As2O5 36.86, total 99.56. The empirical formula, based on 20 O apfu, is (K2.81Ca0.01)∑2.82(Cu7.02Fe3+ 0.95Al0.08Zn0.04Ti0.02)∑8.11(As3.97P0.01)∑3.98O20. Melanarsite is monoclinic, C2/c, a = 11.4763(9), b = 16.620(2), c = 10.1322(8) Å, β = 105.078(9)°, V = 1866.0(3) Å3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 9.22(100)(110), 7.59(35)(1₃11), 6.084(17) (111), 4.595(26)(1₃31, 220, 2₃21), 3.124(22)(3₃31, 1₃51), 2.763(20)(400, 1₃52), 2.570(23)(043) and 2.473(16) (260, 2₃61, 350). Melanarsite has a novel structure type. Its crystal structure, solved from single-crystal X-ray diffraction data (R = 0.091), is based upon a heteropolyhedral pseudo-framework built by distorted Cu(1–3)O6 and (Fe,Cu)O6 octahedra and As(1–3)O4 tetrahedra. Two crystallographically independent K+ cations are located in the tunnels and voids of the pseudo-framework centring eight- and seven-fold polyhedra. The name reflects the mineral being an arsenate and its black colour (from the Greek μέλαν, black).

Andychristyite, PbCu2+Te6+O5(H2O), is a new tellurate mineral from Otto Mountain near Baker, California, USA. It occurs in vugs in quartz in association with timroseite. It is interpreted as having formed from the partial oxidation of primary sulfides and tellurides during or following brecciation of quartz veins. Andychristyite is triclinic, space group P1̄, with unit-cell dimensions a = 5.322(3), b= 7.098(4), c = 7.511 (4) Å, α = 83.486(7), β = 76.279(5), γ = 70.742(5)°, V = 260.0(2) Å3 and Z = 2. It forms as small tabular crystals up to ∼50 μm across, in sub-parallel aggregates. The colour is bluish green and the streak is very pale bluish green. Crystals are transparent with adamantine lustre. The Mohs hardness is estimated at between 2 and 3. Andychristyite is brittle with an irregular fracture and one perfect cleavage on {001}. The calculated density based on the empirical formula is 6.304 g/cm3. The mineral is optically biaxial, with large 2V, strong dispersion, and moderate very pale blue-green to medium blue-green pleochroism. The electron microprobe analyses (average of five) provided: PbO 43.21, CuO 15.38, TeO3 35.29, H2O 3.49 (structure), total 97.37 wt.%. The empirical formula (based on 6 O apfu) is: Pb0.98Cu2+0.98Te6+1.02O6H 1.96. The Raman spectrum exhibits prominent features consistent with the mineral being a tellurate, as well as an OH stretching feature confirming a hydrous component. The eight strongest powder X-ray diffraction lines are [dobs in Å(I)(hkl)]: 6.71(16)(010), 4.76(17)(110), 3.274(100)(120,102,012), 2.641(27)(102, 211, 112), 2.434(23)(multiple), 1.6736(17)(multiple), 1.5882(21)(multiple) and 1.5133(15)(multiple). The crystal structure of andychristyite (R1 = 0.0165 for 1511 reflections with Fo > 4σF) consists of stair-step-like hcp polyhedral layers of Te6+O6 and Cu2+O6 octahedra parallel to {001}, which are linked in the [001] direction by bonds to interlayer Pb atoms. The structures of eckhardite, bairdite, timroseite and paratimroseite also contain stair-step-like hcp polyhedral layers.

The crystal structure of gianellaite, [(NHg2)2](SO4)(H2O)x, cubic, F4̄3m, a = 9.521(6) Å V = 863.1(1.6) Å3, Z = 4, was solved by direct methods and refined to an R 1 index of 2.1% based on 167 unique observed reflections collected on a three-circle rotating-anode (MoKα X-radiation) diffractometer equipped with multilayer optics and an APEX-II detector. In the structure of gianellaite, nitrogen-centred (NHg4)5+ tetrahedra share all corners to form a framework of tetrahedra with an ordered arrangement of interstitial (SO4)2– tetrahedra that show strong orientational disorder. Infrared spectroscopy in the principal O–H stretching region shows peaks at ∼3300 and 1600 cm–1, indicating the presence of (H2O), the position(s) of which could not be discerned in difference-Fourier maps.

An oxide-silicate occurrence, containing >40 wt.% NiO whole rock and showing enrichment in the platinum-group elements and antimony, was investigated at high magnification. Many phases with grain sizes generally <100 μm were observed; electron microprobe analysis indicated that, although some of these are known minerals in Ni–Sb–As space (such as breithauptite and orcelite), most of them cluster around the following compositions: Ni3Sb, Ni3(Sb,As), Ni3As, Ni5(Sb,As)2, Ni7(Sb,As)3 and Ni11(Sb,As)8. Such phases have been observed in synthetic systems, but up to now not in nature. The data reported here therefore probably represent the compositions of new minerals.

Industrial minerals, particularly bentonites, have long been used in treatments to improve the stability and shelf life of white wines. We evaluated a new combination of rocks and minerals, including steam-treated bentonites and natural zeolites (chabazite and phillipsite), to greatly reduce the risk of protein and tartaric instability of wines. Detailed mineralogical, chemical and electrokinetic studies of these materials were conducted using powder X-ray diffraction (PXRD), X-ray fluorescence (XRF), microporosimetry, BET surface-area analysis and zeta-potential measurements. Several model wine solutions containing Bovine Serum Albumin (BSA) were prepared to evaluate the oenological performance of the rock/mineral combinations. UV-VIS spectrophotometry and ion chromatography were used to evaluate the degree of wine stabilization from the protein and tartaric point of view.

The experimental results showed that steam treatment modifies both the microporosity and external surface area of the bentonite. These changes in surface area, along with creation of hydrophobic surfaces, significantly modified the behaviour of the steam-treated bentonites, requiring an increase in the amount of material necessary to bring the protein content to required levels. An important benefit derived from the use of steam-treated bentonites is that the pre-mixing with water before addition to wine is not necessary, as the material is readily dispersed. Finally, the addition of natural zeolites effectively decreased the potassium content, thereby improving the tartaric stability of white wines. In addition, this procedure results in minimal waste, as the bentonite-zeolite mixture can be reused as soil amendments in agriculture.

Kuratite, ideally Ca4(Fe2+10Ti2)O4[Si8Al4O36], the Fe2+-analogue of rhönite and a new member of the sapphirine supergroup, was identified from the D'Orbigny angrite meteorite by electron microscopy and micro-Raman spectroscopy. Based on the least-squares refinement of 25 d-spacings measured from selected-area electron diffraction patterns of 11 zone axes, the symmetry of kuratite was shown to be triclinic (space group by analogy to rhönite) with a = 10.513(7), b = 10.887(7), c = 9.004(18) Å, α = 105.97(13), β = 96.00(12), γ = 124.82(04)°, V = 767 ± 2 Å3 and Z = 1 for the 40 oxygen formula. The empirical formula based on eight electron microprobe analyses is (Ca3.88Na0.02REE3+0.03Mn0.03Mg0.01Ni0.02Zn0.01Sr0.01)∑4.01 (Fe2+9.989.9Ti2.00)∑11.98(Si7.80Al3.52Fe3+0.64P0.05S0.02)∑12.03O39.98F0.01Cl0.01. The simplified formula is Ca4(Fe2+10Ti2)O4[Si8Al4O36]. Micro-Raman spectroscopy showed four main bands resembling those of lunar rhönite but with higher frequencies due to different chemical composition. Analogous to the occurrence of kuratite in terrestrial basaltic rocks, kuratite coexisting with Al, Ti-bearing hedenbergite, ulvöspinel, iron-sulfide, tsangpoite, Ca-rich fayalite and kirschsteinite in D'Orbigny angrite most probably was formed at >1000°C by rapid cooling of an interstitial melt, which is subsilicic, almost Mg-free but enriched in Al-P-Ca-Ti-Fe.

The epidote-group nomenclature report by Armbruster et al. (2006) provides a clear and concise definition of the epidote group, and a set of consistent rules and naming conventions for establishing new subgroups and mineral species within what is now the epidote supergroup (Mills et al., 2009). In order to comply with these rules, it was decided to rename the already approved minerals hancockite, niigataite and tweddillite to epidote-(Pb), clinozoisite-(Sr) and manganipiemontite-(Sr), respectively. These names were already well established within the mineral community, and the renaming caused some controversy. Recent International Mineralogical Association guidelines (Hatert et al. 2013) have given priority to the historical provenance of names over nomenclature consistency. Hatert et al. (2013) state as a main principle that "retroactivity will not be applied", but that "Every change in nomenclature has to go through the CNMNC, and is examined on its own merit", thus establishing a mechanism for re-instating historical names on a case by case basis. The CNMNC (Commission on New Minerals, Nomenclature and Classification Committee of the International Mineralogical Association) has therefore decided, as an exception to the main principle, to re-instate hancockite, niigataite and tweddillite. In part to maintain the historical names but, more importantly, re-establish the link between the mineral names and their structural and chemical definitions.

A CO-bearing member of the hydroxylapatite–hydroxylellestadite series occurs as a Si-rich part of a hydroxylapatite–hydroxylellestadite series mineral (hydroxylapatitess) in a skarn xenolith from Tadano, Fukushima Prefecture, Japan. Hydroxylapatitess is composed of Si-poor and Si-rich parts. The Si-poor part is F-rich hydroxylapatite. The infrared spectrum of the Si-rich part demonstrates the presence of B-type CO3. A representative analysis of the Si-rich part yielded the empirical formula Ca4.989[(PO4)1.315 (SiO4)0.848 (SO4)0.368(CO2.943)0.480]∑3.011(OH0.629 Cl0.264 F0.107)∑1.000 on the basis of 8 cations, assuming Si = S + C. There is a very strong inverse correlation between Si and P in both the Si-poor and Si-rich parts. These data indicate that the substitution mechanism (SO4,CO3)2– + (SiO4)4– = 2(PO4)3– probably occurs in hydroxylapatite ss. Therefore, it was concluded that the Si-rich part corresponds to a CO3-bearing hydroxylapatite–hydroxylellestadite series mineral with CO3 partially replacing SO4. Most of the Si-rich part shows CO3 > SO4 and its composition approaches Ca5(SiO4)1.5(CO3,SO4)1.5(OH,Cl,F).

Tvrdýite, Fe2+Fe3+2A13(PO4)4(OH)5(OH2)4·2H2O, is a new phosphate mineral from the abandoned Huber open pit, in the Krásno ore district near Horní Slavkov, western Bohemia, Czech Republic. It was found along with Al-rich beraunite, fluorapatite and pharmacosiderite in a cavity of quartz gangue. Tvrdýite forms acicular to fibrous crystals with diameters in the range 0.5–5 μm and lengths up to 300 μm, partly grouped in radiating aggregates up to 3 mm in size. It has a silvery to olive, greyish green colour with pearly lustre, greyish-white streak and is very brittle with an uneven fracture; individual fibres are somewhat flexible. Cleavage on {100} is good; the Mohs hardness is ∼3–4. The calculated density is 2.834 g cm–3. Tvrdýite is optically biaxial (–), with α = 1.650(2), β = 1.671(1) and γ = 1.677(1) (white light); 2V = 56(1)°; dispersion: r > v, strong; optical orientation: Z = b, X ≈ a, Y ≈ c; pleochroism: X = greenish blue, Y = yellowish orange, Z = yellowish orange (X>> Y > Z). Tvrdýite is monoclinic, space group C2/c, a = 20.564(4), b = 5.101(1), c = 18.883(4) Å, β = 93.68(3)° and V = 1976.7(7) Å3, Z = 4, a:b:c= 4.031:1:3.702. The strongest eight lines in the powder X-ray diffraction (XRD) pattern [d in Å (I)(hkl)] are 10.227 (100) (200), 9.400 (6) (002), 7.156 (14) (202), 5.120 (7) (400), 3.416 (11) (600), 3.278 (6) (602), 2.562 (5) (800) and 2.0511 (3) (10,0,0). Chemical analyses by electron microprobe yielded MnO 0.01, ZnO 5.08, , FeO 4.31, Fe2O3 21.16, Al2O316.71, P2O5 32.64, As2O5 2.56, F 0.53, H2O (calc.) 17.84, O = F –0.22, total 100.62 wt.%. The resulting empirical formula, calculated on the base of 27 anions, obtained from the crystal structure, is Zn0.52Fe2+0.50Fe3+2.21Al2.75(PO4)3.86(AsO4)0.19OH4.60F0.23(OH2)4·2H2O. The ideal formula, Fe2+Fe3+2Al3(PO4)4(OH)5(OH2)4-2H2O, requires FeO 8.75, Fe2O3 19.44, Al2O3 18.62, P2O5 34.56, H2O 18.64, total 100.00 wt.%. The crystal structure of tvrdýite was solved from single-crystal data (synchrotron beamline) and refined to R1 = 0.038 for 2276 reflections with I > 2σ(I). Tvrdýite is isostructural with beraunite, but contains dominant Al in two of the four independent M sites, which are all occupied by Fe in beraunite.

Vanadium, V, is a new mineral found in sublimates of high-temperature fumaroles of the Colima volcano, Mexico. The mineral precipitates over a narrow temperature range of 550–680°C, and occurs in association with colimaite (K3VS4) and shcherbinaite (V2O5). Native vanadium was been found on the inner wall of an inserted silica tube and subsequently in the adjacent rock of the Z3 fumarole. Vanadium forms smooth, irregular to flattened crystals, 5–20 μm in diameter. Smaller irregular crystals have also been observed in silica tubes. Due to its small crystal size, its physical properties (hardness, cleavage and density) could not be determined. An EDS spectrum indicated the presence of V, Fe, Al and Ti with an empirical formula calculated on the basis of EPMA analyses of V0.86Fe0.09Al0.04Ti0.01. Gandolfi and glancing-angle X-ray diffraction data showed that the microcrystals were body-centred cubic, space group Im3̄m, a = 3.022(3) Å, V = 27.60 (5) Å3, Z = 2. The five strongest calculated diffraction lines are [ d spacings in Å, (I) (hkl)]: 2.1411 (100)(110), 1.5126 (12)(200), 1.2301 (19)(211), 0.9565 (8)(310) and 8.8090 (11)(321). The calculated density is 6.033 g cm–3. Thermochemical modelling was used to explain why very oxidized gas at Colima precipitates V-bearing minerals and some native elements (vanadium and gold). Vanadium, is the second newly recognized mineral species (after colimaite) collected from an active fumarole in this volcanic crater. The mineral and its name have been approved by the CNMNC (IMA 2012-021a).

In order to define the cathodoluminescence (CL) properties of magmatic topaz and its relation with trace-element composition, we studied topaz phenocrysts from the Ary-Bulak ongonite massif, Russia using a wide array of analytical techniques. Scanning electron microscopy CL panchromatic images reveal strong variations, which define micrometre-scale euhedral growth textures. Several truncations of these growth textures occur in single grains implying multiple growth and resorption events. The CL-spectra of both CLbright and -dark domains have a major peak in the near-ultraviolet centred at 393 nm. Cathodoluminescence images taken after several minutes of electron bombardment show decreasing emission intensity. Electron microprobe analyses indicate high F concentrations (average OH/(OH + F) = 0.04 calculated by difference, 100 wt.% – total from electron probe microanalyses), consistent with what has been found previously in topaz-bearing granites, and the OH stretching vibration (∼3653 cm–1) was detected in Raman spectra. Laser ablation inductively-coupled plasma mass spectrometry traverses performed across the CL textures detected trace elements at ppm to thousands of ppm levels, including: Fe, Mn, Li, Be, B, P, Nb, Ta, W, Ti, Ga, light rare-earth elements, Th and U. Lithium, W, Nb and Ta appear to be correlated with CL intensity, suggesting a role for some of these elements in the activation of CL in topaz. In contrast, no clear correlation was found between CL intensity and F contents, despite the fact that the replacement of OH for F is known to affect the cell parameters of topaz.