Nordgauite, MnAl2(PO4)2(F,OH)2·5H2O, is a new secondary phosphate from the Hagendorf-Süd pegmatite, Bavaria, Germany. It occurs as white to off-white compact waxy nodules and soft fibrous aggregates a few millimetres across in altered zwieselite—triplite. Individual crystals are tabular prismatic, up to 200 μ long and 10 μ wide. Associated minerals include fluorapatite, sphalerite, uraninite, a columbite—tantalite phase, metastrengite, several unnamed members of the whiteite—jahnsite family, and a new analogue of kingsmountite. The fine-grained nature of nordgauite meant that only limited physical and optical properties could be obtained; streak is white; fracture, cleavage and twinning cannot be discerned. Dmeas. and Dcaic. are 2.35 and 2.46 g cm–3, respectively; the average RI is n = 1.57; the Gladstone-Dale compatibility is —0.050 (good). Electron microprobe analysis gives (wt.%): CaO 0.96. MgO 0.12, MnO 14.29, FeO 0.60, ZnO 0.24, A12O3 22.84, P2O5 31.62, F 5.13 and H2O 22.86 (by CHNX less F=O 2.16, total 96.50. The corresponding empirical formula is (Mn0.90Ca0.08Fe0.04Zn0.01Mg0.01)-Σi.04Ai2.0i(PO4)2[F1.21,(OH)0.90]Σ2.11·5.25H2O. Nordgauite is triclinic, space group P1̄, with the unit-cell parameters: a = 9.920(4), b = 9.933(3), c = 6.087(2) Å, α = 92.19(3), β = 100.04(3), γ = 97.61(3)°, V = 584.2(9) Å3 and Z = 2. The strongest lines in the XRD powder pattern are [d in Å (I) (hkl)] 9.806 (100)(010), 7.432 (40)(l1̄0), 4.119 (20)(210), 2.951 (16)(031), 4.596 (12)(21̄O), 3.225 (12)(220) and 3.215 (12)(121). The structure of nordgauite was solved using synchrotron XRD data collected on a 60 μm × 3 μm × 4 μm needle and refined to R1 = 0.0427 for 2374 observed reflections with F > 4σ(F). Although nordgauite shows stoichiometric similarities to mangangordonite and kastningite, its structure is more closely related to those of vauxite and montgomeryite in containing zig-zag strings of corner-connected Al-centred octahedra along [011], where the shared corners are alternately in cis and trans configuration. These chains link through corner-sharing with PO4 tetrahedra along [001] to form (100) slabs that are interconnected via edge-shared dimers of MnO6 polyhedra and other PO4 tetrahedra.

The accurate measurement of trace element concentrations in natural sulphides by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been limited by the lack of matrix-matched calibration standards. The synthesis of a standard, IMER-1, by incorporating four minor and 34 trace elements into a chalcogenide glass matrix Ge28Sb12S60 is reported here. Chemical analysis by electron probe microanalysis (EPMA), LA-ICP-MS, solution ICP-MS, and inductively coupled plasma-optical emission spectroscopy (ICP-OES) confirmed the excellent homogeneity of major elements (1-σ relative standard deviation (RSD) <1% for S, Sb and Ge) and acceptable homogeneity of most trace elements (1-σ RSD <10%). The standard was validated by analysing trace-elements concentrations in three geological pyrite specimens using IMER-1 as the calibration standard and comparing the results to previously reported values also determined by LA-ICP-MS but using a different calibration standard. STDGL2b-2. The results suggest that IMER-1 may be an appropriate calibration standard for LA-ICP-MS analysis of trace elements in natural sulphides.

Diagenetic pyrite from the Silurian continental red bed-hosted Transfiguration cupriferous deposit in the Quebec Appalachians, Gaspe Belt, Canada, contains up to ∼2% (m/m) Pb. This large Pb content in pyrite contrasts with experimental determinations that indicate solubility of <0.1% (m/m) PbS in pyrite at high temperature. The distribution of Pb in pyrite is heterogeneous, with plumbiferous domains occurring as patches and concentric growth layers alternating with Mn- and Mo-bearing zones. The plumbiferous pyrite is surrounded by As- and Cu-rich rims. This compositional heterogeneity, however, is elusive under normal backscattered-electron (BSE) imaging, but it can be recognized under high-gain BSE. Proton-induced X-ray emission (PIXE) confirms the presence of Pb. Plumbiferous pyrite with >0.1% (m/m) Pb has rarely been described; it is thus possible that plumbiferous pyrite may have been overlooked in metalliferous deposits worldwide. The plumbiferous pyrite from Transfiguration has a light S-isotope composition that is characteristic of bacterial sulphate reduction. We suggest that Pb in diagenetic pyrite indicates Pb-tolerant bacterial activity and, perhaps, constitutes a biosignature of bacterial tolerance to Pb in ancient sedimentary systems.

The Szklary holtite is represented by three compositional varieties: (1) Ta-bearing (up to 14.66 wt.% Ta2O5), which forms homogeneous crystals and cores within zoned crystals; (2) Ti-bearing (up to 3.82 wt.% TiO2), found as small domains within the core; and (3) Nb-bearing (up to 5.30 wt.% Nb2O5,) forming the rims of zoned crystals. All three varieties show variable Sb+As content, reaching 19.18 wt.% Sb2O3 (0.87 Sb a.p.f.u.) and 3.30 wt.% As2O3 (0.22 As a.p.f.u.) in zoned Ta-bearing holtite, which constitutes the largest Sb+As content reported for the mineral. The zoning in holtite is a result of Ta-Nb fractionation in the parental pegmatite-forming melt together with contamination of the relatively thin Szklary dyke by Fe, Mg and Ti. Holtite and the As- and Sb-bearing dumortierite, which in places overgrows the youngest Nb-bearing zone, suggest the following crystallization sequence: Ta-bearing holtite → Ti-bearing holtite → Nb-bearing holtite → As- and Sb-bearing, (Ta,Nb,Ti)-poor dumortierite → As- and Sb-dominant, (Ta,Nb,Ti)-free dumortierite-like mineral (16.81 wt.% As2O3 and 10.23 wt.% Sb2O3) with (As+Sb) > Si. The last phase is potentially a new mineral species. Al6□☐(Sb,As)3O15, or Al5☐2B(Sb,As)3O12(OH)3, belonging to the dumortierite group. The Szklary holtite shows no evidence of clustering of compositions around ‘holtite I’ and ‘holtite II'. Instead, the substitutions of Si4+ by Sb3++As3+ at the Si/Sb sites and of Ta5+ by Nb5+ or Ti4+ at the Al(l) site suggest possible solid solutions between: (1) (Sb,As)-poor and (Sb,As)-rich holtite; (2) dumortierite and the unnamed (As+Sb)-dominant dumortierite-like mineral; and (3) Ti-bearing dumortierite and holtite. i.e. our data provide further evidence for miscibility between holtite and dumortierite, but leave open the question of defining the distinction between them. The Szklary holtite crystallized from the melt along with other primary Ta-Nb-(Ti) minerals such as columbite-(Mn), tantalite-(Mn), stibiotantalite and stibiocolumbite as the availability of Ta decreased. The origin of the parental melt can be related to anatexis in the adjacent Sowie Mountains complex, leading to widespread migmatization and metamorphic segregation in pelitic-psammitic sediments metamorphosed at ∼390—380 Ma.

The structure of perloffite, ideally BaMn22+Fe23+(PO4)3(OH)3, has been solved and refined from single-crystal X-ray data collected on a Sr-bearing sample from the Spring Creek copper mine, near Wilmington, South Australia. A fragment of the crystal used for the collection of the X-ray intensity data was analysed by electron microprobe. The resulting unit formula is (Ba1.00,Sr0.03Σ1.03) (Mn2+1.15,Fe2+0.76Ca0.05Mg0.02,Na0.01)Σ1.99(Fe3+1.94,Al0.06)Σ2.00(PO4)2.99(OH)3.04. The structure is monoclinic. space group P21/m, a = 9.2425(18), b = 12.470(3), c = 5.002(1) Å, 0 = 100.19(3)°, V = 567.41(19) Å3, Z = 2, and was refined to R1 = 4.71% for 1568 unique observed reflections. The X site is [11]-coordinated and is occupied by dominant Ba and minor Sr, with an <X—O< distance of 2.953 Å. The Ml site is octahedrally coordinated and is occupied by Mn2+and Fe2+ plus minor Ca, Mg and Na with an observed <M1—O> distance of 2.208 Å. The M2 site is also octahedrally coordinated and is occupied by Fe3+ plus minor Al with a <M2—O> distance of 2.018 A. Perloffite is isostructural with other members of the bjarebyite group. Edge-linked [M22O6(OH)4] dimers link via corners to form chains along [010]. Chains are decorated with PO4 tetrahedra and link in the a direction via [M1O5(OH)] octahedra and (Ba,Sr) atoms to form a complex framework. The H2 atom hydrogen-bonds strongly to the O3 anion, providing additional linkage between chains.

Iangreyite, ideally Ca2Al7(PO4)2(PO3OH)2(OH,F)15·8H2O, is a new mineral (IMA2009-087) from the Silver Coin mine, Nevada, USA and the Krásno ore district, Horní Slavkov, Czech Republic. At Silver Coin, iangreyite occurs as thin, colourless to white or cream, hexagonal tablets up to 0.4 mm in diameter and 0.02 mm thick associated with meurigite-Na, plumbogummite, kidwellite, lipscombite. strengite, chalcosiderite, wardite, leucophosphite, wavellite, goethite, barite, quartz and F-rich perhamite. At Krásno, white, yellowish or light pink iangreyite coatings consist of 0.3 mm wide clusters of minute and very thin intergrown tabular crystals with a maximum diameter of 0.2 mm. Individual iangreyite crystals are transparent with a vitreous lustre, while iangreyite clusters tend to be pearly and translucent. The estimated hardness is 3 on the Mohs scale, the fracture is irregular and the mineral is non-fluorescent under SW and LW ultraviolet light. Individual crystals are somewhat flexible and there is perfect cleavage on ﹛001﹜. The density (Silver Coin), measured by the sink-float method in an aqueous solution of sodium polytungstate, is 2.46(3) g/cm3, while the calculated density is 2.451 g/cm3. Crystals from Silver Coin are uniaxial (+), with the indices of refraction: ε = 1.544(2) and s = 1.554(2), measured in white light, and are non-pleochroic. The empirical formula for iangreyite from Silver Coin (calculated on the basis of 39 anions per formula unit) is: Ca1.42K0.22Na0.09Ba0.03 Sr0.01Al6.51Mg0.09Fe0.02Cu0.01Zn0.01P3.81F5.24H30.21O33.76, while the empirical formula from Krásno is: Ca2.15K0.10Na0.01Ba0.02Sr0.12Al6.28Mg0.01Fe0.12Cu0.08Zn0.01P3.64Si0.43F4.65H29.62O34.35. Iangreyite is trigonal, space group P321 and Z = 1, with the unit-cell parameters (Silver Coin): a = 6.988(1), c = 16.707(3) Å and V= 706.5(2) Å3 and (Krasno): a = 6.989(1), c = 16.782(4) Å and V = 709.8(2) Å3. The structure of iangreyite, modelled from powder data, consists of blocks of the crandallite-type structure that are interconnected along c via corner-sharing of crandallite-block PO4 tetrahedra with A1O2(OH)3 bipyramids. This linkage generates large channels along [110] bounded by 10-member rings of octahedra, tetrahedra and trigonal biyramids, that are occupied by Ca and water molecules.

The crystal structure of new lead chloride arsenite, Pb5(As3+O3)Cl7 [orthorhombic, Pbcn, a = 16.894(2), b = 10.913 (1), c = 16.760(2) Å, V = 3090.1(7) Å3], from the historic slags of Lavrion, Greece, has been solved by direct methods and refined to R1 = 0.069. The structure contains five symmetrically unique Pb, one As, eight Cl and three O sites. The As atom forms three nearly equal As—O bonds which result in the formation of an AsO3 trigonal pyramid with As at the apex. The Pbl. Pb2, Pb3 and Pb4 atoms are bonded to the AsO3 groups via Pb2+—O bonds to form complex [Pb4(AsO3)] chains parallel to the b axis. The Pb(5) atom is coordinated solely by Cl– anions. The resulting Pb(5)Cl7 polyhedra share common edges and corners to produce bent chains parallel to the c axis. A short compilation of structural features of known lead chloride arsenites is given.

A quantitative determination of Fe3+/ΣFe ratios using the electron microprobe is presented for glasses. The measurements are based on the shift of the Fe-Lα peak position between Fe3+ and Fe2+, resulting from differences in self-absorption. We present new calibration curves for glasses with Fe contents as low as 2 wt.% Fe.

This method was used for glasses from a metasomatized spinel Iherzolite (Massif Central, France) in which highly vesicular glass associated with secondary minerals occurs in reaction pockets around corroded Cr-spinels. The glass was found to be oxidized homogeneously with Fe3+/ΣFe ≈ 0.70 (measured with an uncertainty of ±0.06), in contrast with the value of ∼0.15 that would correspond to the former melt under fo2 conditions inferred from secondary minerals. The glass oxidation probably results from the dissociation of the melt-water content under degassing, prior to local hematite depositions (spinel rims and crack fillings).

The unit-cell parameters of andalusite and sillimanite have been measured by high-T powder X-ray diffraction up to 1000°C at ambient pressure. Within the temperature range investigated, all the unit-cell parameters varied smoothly, indicating no phase transition. The volume-temperature data were fitted with a polynomial expression for the thermal expansion coefficient (αT = a0 + a1T + a2T-2). yielding a0 = 2.55(2) × 10–5K–1, al = 0 and a2 = 0 for andalusite, and a0 = 1.40(4) × 10–5K–1a1 = 7.1(8) × 10–9K–2 and a2 = 0 for sillimanite. Using the new thermal expansion data determined in the present study and compressional data from the literature, the P-T phase relations of the kyanite-andalusite-sillimanite system were calculated thermodynamically, with the invariant point located at ∼523°C and 3.93 kbar.

The Zn-bearing beaverite of Sato et al. (2008) has been named ‘beaverite-(Zn)’ in accordance with the alunite supergroup nomenclature of Bayliss et al. (2010), and data for the mineral have been approved by the IMA-CNMNC. Beaverite-(Zn) occurs as a dark-brown secondary mineral in the hydrothermal Cu-Zn-Pb ore deposit of the Mikawa mine, Niigata Prefecture, Japan. Electron microprobe analysis gave an empirical formula of Pb0.95(Fe1.88Al0.10)(Zn0.83Cu0.03)(SO4)2[(OH)5.36O0.38] on the basis of S = 2. The Rietyeld analysis (Sato et al, 2008) indicated it to be trigonal, R3̄m, a = 7.3028(2), c = 17.0517(4) Å, V = 787.56(4) Å3.

Dellaite crystals of close to end-member composition, Ca6(Si2O7)(SiO4)(OH)2, and with ∼1.5 wt.% Cl. yielding Ca6(Si2O7)(SiO4)(OH)1.75Cl0.25 have been found in skarns within the gabbroid rocks of the Birkhin complex (Eastern Siberia, Russia). The greatest Cl content analysed in a dellaite domain in this skarn is 5.2 wt.% Cl corresponding to 0.8 Cl p.f.u. Dellaite occurs in altered merwmite-larnite-bredigite-gehlenite skarns and also in calcio-olivine skarns with residual larnite. The crystal structures of Cl-free and Cl-bearing (∼1.5 wt.% Cl) dellaite have been refined, including hydrogen positions, from single-crystal X-ray data to R1 = 3.7 and 3.8%, respectively. In addition, both dellaite varieties were studied by Raman spectroscopy indicating stronger hydrogen bonds for the Cl-bearing sample, which agrees with the structural data. Cl is strongly selective and enriches at one (O6) of the two OH positions allowing for the formation of a stronger hydrogen bond O8—H8…C16 compared to O8—H8…O6. Raman spectra of the domain with ∼0.8 Cl p.f.u. confirm the general enhancement of a low-frequency band in the OH range suggesting the dominance of the O—H…Cl hydrogen bond systems.

Dellaite and killalaite, Ca3.2(H0.6Si2O7)(OH), have related modular structures, differentiated only by the Si2O7 units in killalaite and alternating Si2O7 and SiO4 units in dellaite. The similarity in cell dimensions and chemical composition suggests that trabzonite, Ca4Si3Oi0-2H2O, with Si3Oi0 trimers also belongs to the same family of structures.