An examination has been carried out of ten specimens assigned to the group. These include metatype specimens of neotocite (Gestrikland, Sweden) and penwithite (Wheal Owles, Penwith, Cornwall) and topo-type specimens of stratopeïte (Pajsberg, Sweden), klipsteinite (Herborn, Dillenberg, Germany), and opsimose (specimen labelled klipsteinite, but from Klapperud, Dalecarlia, Sweden). The investigation arose out of the recent find of neotocite at the Geevor mine, Cornwall, close to the site of the type locality for penwithite.

In the investigation klipsteinite has been confirmed as a mixture (Fisher, 188o), the dominant mineral in the mixture giving an X-ray pattern close to birnessite. Chemical analyses, refractive indices, and specific gravity determinations are given for the remainder in the miniprint section, p. M27 (Table I). They show that the group can be represented fairly closely by the formula (Mn, Fe)SiO3.H2O, but with significant carbonate present in each sample. CO2 has not generally been reported before in these minerals and the water content is lower than previous analyses, as a result of the precautions taken in drying the material before analysis (over magnesium perchlorate at room temperature).

The specimens examined are all dark brown or black in appearance (often darkening on exposure to light) with a vitreous lustre and conchoidal fracture. The group should be regarded as poorly crystalline since all the specimens gave similar X-ray powder patterns with three very broad and diffuse lines around 3·5, 2·6, and 1·6 Å respectively (see Whelan and Goldich, 1961). After heating to 1000 °C all form braunite, with the exception of stratopeite, which gave an X-ray powder pattern closer to pyroxmangite. Hausmannite or spinel were also found associated with braunite in several specimens.

The full text includes the results of differential thermal analysis and infra-red spectra from the samples.

Of the names used in the group, opsimose (Beudant, 1832) was the first recorded, but in this and the subsequent work of Bahr (1850), it was associated with material much richer in manganese. Wittingite and neotocite (Nordenskiöld, 1849) were -named separately on account of the higher iron content of neotocite. Stratopeïte (Igelström, 1851) is a magnesium-bearing variety, while penwithite (Collins, 1878, 1879) was thought to have a different manganese valency state from wittingite.

In view of its current widespread usage and the fact that neotocite was originally named for an iron-bearing manganese silicate it is proposed that neotocite be defined as the group of poorly crystalline manganese silicates with formulae close to (Mn, Fe)SiO3.H2O and Mn > Fe. With Fe > Mn the series grades into hisingerite. Limited substitution of MgO, Al2O3, and CO2 should be acceptable. Finally it has been proposed that the other names be discarded. The Commission on New Minerals and Mineral Names, IMA, has approved these proposals, but came to no firm conclusion as to whether the group name should be spelt ‘neotocite’ or as in the original description ‘neotokite’. Accordingly either are permissible.

Sark's Hope silver-lead lode, which was mined during the 1830s and 1840s cuts a Late Precambrian granite at the southernmost point of the island of Sark. The primary ore assemblage is pyrite, galena, chalcopyrite, tennantite, tetrahedrite, sphalerite, marcasite, arsenopyrite, pyrrhotine, bravoite, enargite, and the silver minerals pyrargyrite, pearceite, polybasite, and acanthite. Gangue minerals are hematitic quartz, calcite, and illite. Alteration products include chalcosine, covelline, blaubleibender covelline, limonite, malachite, azurite, cerussite, and anglesite. The generalized paragenesis is of early Fe, Co, Ni, As, and S species and later minerals of Pb, Cu, Ag, Zn, Fe, As, Sb, and S. The earliest alteration products are copper sulphides; these are followed by lead and copper carbonates and sulphates, and hydrated iron and manganese oxides. Growth zoning is a common feature of many of the ore minerals, and electron microprobe analysis shows that this is sometimes related to compositional differences. Tetrahedrite and tennantite, particularly, exhibit a wide range of compositions.

The lead silicate minerals from Franklin, New Jersey, occurred in two separate assemblages. One of these is characterized by esperite associated with hardystonite and occasional larsenite. The second assemblage can be considered as two parts: one consists of margarosanite, barysilite, nasonite, and ganomalite; the other contains roeblingite and hancockite, together with a number of highly hydrated phases. Chemical analyses indicate that these species conform to their theoretical compositions. There are no simple lead silicates at Franklin; all are compound silicates of Pb with Mn, Zn, and Ca.

Zoned hibonites from a kalsilite, leucite, spinel, corundum, perovskite gneiss from the southern Indian granulite terrain near Punalur, Kerala, have rims that are the most Ti-rich yet recorded (0.83–0.87 Ti atoms per 19 O) and are essentially free of REE elements (ΣREE < 0.01 atoms per 19 O) while the cores are the most REE-rich compositions yet recorded (ΣREE = 0.55–0.65 atoms per 19 O). Within the limits of analytical uncertainty, the compositions of the hibonite can be related to the theoretical end-member CaAl12O19 by the substitutions REE R2+ ⇌ CaAl and R2+R4+ ⇌ Al2 with the REE-rich cores containing in excess of 50% of the REE R2+ Al11O19 end member. Minor substitution of Na for Ca occurs in the rims, while non-stoichiometry in both the cores and rims is indicated by partial 12-fold site occupancy. Ion-microprobe analysis of the REE-rich hibonites reveals strong enrichment in LREE with La/Lu c. 250 000.

FREE energies of formation of boleite, Pb26Cu24 Ag9Cl62(OH)47·H2O, and pseudoboleite, Pb5Cu4 Cl10(OH)8·2H2O, have been determined from solution studies at 298.2 K. ΔG°f values for the minerals are −19097.9±4.1 and −3705.4±5.5 kJ mol−1 respectively. These values, together with results of earlier studies (Humphreys et al., 1980) have been used to construct the stability field diagram shown in fig. 1. The boundaries for boleite and pseudoboleite are shown separately. If fields for the two minerals are plotted together, boleite has no thermodynamic stability at the silver ion activity chosen. At higher activities of Ag+(aq) the boleite field is negligible in extent.

The results can, however, be rationalized in terms of kinetics of mineral formation, rather than thermodynamic considerations alone. Since pseudoboleite is never found without boleite upon which it is observed to grow epitaxially (Winchell, 1963), it is clear that boleite must form metastably prior to any pseudoboleite deposition. Accordingly, boleite has a large range of solution compositions, from which it may precipitate. The hatched area of fig. 1 shows this at the Cu2+(aq) and Ag+(aq) activities chosen. The field is terminated at high aCl− by the AgCl line, above which silver is precipitated as AgCl(s), chlorargyrite.

It is also evident from the chemical studies that the deposition of several assemblages in the leadcopper-chloride group of minerals is simply related to variations of chloride activity. With decreasing aCl− the associations cumengeite + boleite + pseudoboleite, diaboleite + boleite + pseudoboleite, and diaboleite + chloroxiphite are expected in turn. This relationship is apparently borne out by field observations of occurrences of the minerals.

Rinkite-(Y), ideally Na2Ca4YTi(Si2O7)2OF3, is a new rinkite-group (seidozerite-supergroup) TS-block mineral from the Darai-Pioz alkaline massif, Tian-Shan mountains, Tajikistan. The mineral is of hydrothermal origin. It occurs as aggregates (up to 1.5 cm long) of acicular crystals 0.1–1.0 mm thick, and as separate elongated columnar, flattened-prismatic crystals up to 1 cm long with rectangular or rhombic sections up to 0.5 mm across. Associated minerals are quartz, aegirine, microcline, neptunite, pectolite, calcite, eudialyte-group minerals, fluorite, titanite, turkestanite, kupletskite, galena, albite and pyrochlore-group minerals. Crystals are transparent and colourless to occasionally white, with a vitreous lustre. Rinkite-(Y) has a white streak, uneven, conchoidal fracture and does not fluoresce under a cathode or ultraviolet light. Cleavage is very good on {100}, no parting was observed, Mohs hardness is ~5, and it is brittle, Dmeas. = 3.44(2) g/cm3, Dcalc. = 3.475 g/cm3. It is biaxial (+) with refractive indices (λ = 590 nm) α = 1.662(2), β = 1.666(2), γ = 1.685(5); 2Vmeas. = 50(3) and 2Vcalc. = 49.7°. It is nonpleochroic. Rinkite-(Y) is monoclinic, space group P21/c, a = 7.3934(5), b = 5.6347(4), c = 18.713(1) Å, β = 101.415(2)° and V = 764.2(2) Å3. The six strongest reflections in the X-ray powder diffraction data [d(Å), I, (hkl)] are: 3.057, 100, (006, $\bar{2}$12, 210); 2.688, 28, (016); 9.18, 24, (002); 2.929, 17, ($\bar{2}$13, 211); 3.559, 15, (104, 014) and 2.783, 14, (021). The empirical formula calculated on 18 (O + F) is Na2.11(Ca3.74Sr0.03Mn0.03)Σ3.80(Y0.50Nd0.16Ce0.16Gd0.07Dy0.06Sm0.05Pr0.03La0.03${\rm U}_{0.01}^{{\rm 4 + }} {\rm )}_{\Sigma 1.07}{\rm (T}{\rm i}_{0.85}{\rm N}{\rm b}_{0.17}{\rm W}^{6+}_{0.01}{\rm T}{\rm a}_{0.01}{\rm )}_{\Sigma 1.04}\left( {{\rm S}{\rm i}_{4.03}{\rm O}_{14}} \right){\rm O}_{1.40}{\rm F}_{2.60}$ with Z = 2. The ideal formula is Na2Ca4YTi(Si2O7)2OF3. The crystal structure was refined on a twinned crystal to R1 = 4.59% on the basis of 1489 unique reflections (F > 4σF) and is a framework of TS (Titanium-Silicate) blocks. The TS block consists of HOH sheets (H – heteropolyhedral, O – octahedral) parallel to (100). In the O sheet, the Ti-dominant [6]MO1 site ideally gives 1 Ti apfu. The [8]MO2 and [6]MO3 sites are ideally occupied by Na and (NaCa) apfu. In the H sheet, the [7]MH site is occupied by Ca1.13Y0.50REE0.37, (REE = rare-earth element), ideally (CaY), <MH–φ> = 2.415 Å and the [7]AP site is occupied by Ca1.81REE0.19, ideally Ca2, <AP–φ> = 2.458 Å. The MH + AP sites ideally give (Ca3Y) apfu. The MH and AP polyhedra and Si2O7 groups constitute the H sheet. Linkage of H and O sheets via common vertices of MH and AP polyhedra and Si2O7 groups with MO1–3 polyhedra results in a TS block. The TS block in rinkite-(Y) exhibits linkage 1 and stereochemistry typical for the rinkite group (Ti = 1 apfu) of the seidozerite supergroup. For rinkite-(Y), the ideal structural formula of the form AP2MH2MO4(Si2O7)2$ \left( {{\rm X}_{\rm M}^{\rm O} } \right)_2\left( {{\rm X}_{\rm A}^{\rm O} } \right)_2{\rm is }\;\left( {{\rm C}{\rm a}_3{\rm Y}} \right){\rm Na}\left( {{\rm NaCa}} \right){\rm Ti}\left( {{\rm S}{\rm i}_2{\rm O}_7} \right)_2\left( {{\rm OF}} \right){\rm F}_2 $ with Z = 2. The mineral is named rinkite-(Y) as it is structurally identical to rinkite-(Ce) and Y is the dominant rare-earth element.

The macroscopic features of a number of Gibeon meteorites have been reviewed and selected specimens have been examined in more detail by metallographic, microprobe, and X-ray diffraction techniques.

A number of specimens appear to have been reheated by man and in these cases reheating temperatures are indicated. Specimens that show no signs of artificial reheating are discussed in relation to the form, distribution, and structure of the kamacite, daubréelite, and troilite. X-ray examination of the kamacite reveals partly annealed shock damage. Small monomineralic inclusions of daubréelite appear to be concentrated in the non-octahedral kamacite and show no signs of alteration By contrast all the troilite has been remelted and has dissolved contiguous plessite and daubréelite. The remelting of troilite appears to have been induced by shock at temperatures below about 450°C.

Five turquoise samples, belonging to the XVII century historical collection of the Real Museo Mineralogico (University of Naples Federico II), were investigated by a multi-methodological approach based on powder X-ray diffraction, electron microprobe analysis in wavelength-dispersive spectroscopy mode, backscattered electron images from scanning electron microscopy in energy-dispersive spectroscopy mode, laser ablation inductively coupled plasma mass spectrometry, Fourier transform infrared and Raman spectroscopy.

The samples originate from Sinai (Egypt), Santa Fè S. Miguel (New Mexico), Saxony (Germany), Montebras Creuse (France) and Nishapur (Khorassan, Iran) and display different mineralogical compositions and various mineral associations. The study has shown the presence of: (1) four minerals of the turquoise group: turquoise, faustite, chalcosiderite and planerite; (2) other phosphates from different groups: wavellite, crandallite, goyazite, gorceixite, variscite, metavariscite, fluorapatite; and (3) other minerals: voltaite, adularia and quartz.

The present investigation is intended to show the mineralogical and geochemical variability of the samples with particular attention to the mineralogical parageneses, textural analyses and trace-element concentrations.

In the UK, most intermediate level radioactive waste is packaged in stainless steel containers. It is important that containers should maintain their integrity for extended periods of storage prior to final disposal. A prototype 4 metre box fabricated from 304S11 stainless steel was monitored at an inland rural building for over twelve years to gain experience in monitoring environmental conditions and corrosion during storage. A wide range of different types of aerosol particles were observed on the surfaces and in the air. They contained corrosive ions such as chloride, as well as other anions such as sulfate and nitrate. The chloride deposition rate was between 0.1 and 4 μg cm−2 yr−1 depending on the orientation and location of the surface, with a chloride/sulfate ratio ranging from ∼0.3–2. The temperature and relative humidity typically ranged from 0–30°C and 40–90%, respectively. The greatest degree of corrosion developed on the base of the box, which had elevated chloride concentrations (10–140 μg cm−2). However, there was little evidence of corrosion propagation on the surface of the box and no evidence of stress corrosion cracking. The average pit propagation rates on a 316L coupon mounted next to the 4 m box were <1 μm yr−1.

Petewilliamsite, ideally (Ni,Co)30(As2O7)15, monoclinic, space group C2, a = 33.256(5), b = 8.482(1), c = 14.191(2) Å, ß = 104.145(3)°, V = 3881.6(11) Å3, a:b:c = 3.9209:1:1.6731, Z = 2, is a new mineral found on a single nickeline-veined quartz specimen from Johanngeorgenstadt, Saxony, Germany. The mineral possesses a pronounced subcell-supercell: a (subcell) = 1/5 a (supercell); b (subcell) = b (supercell); c (subcell) = 1/3 c (supercell), and the strongest six lines of the X-ray powder-diffraction pattern are [d in Å (I) (hkl)]: 4.235(30)(020) ; 3.118(100)(513, 023); 3.005(60); 2.567(50); 1.637(50)(536 ); 1.507(30b)(553, ). It occurs predominantly as scattered patches of mm-sized aggregates which are intimately associated with varicoloured xanthiosite; additional associations include bunsenite, aerugite, rooseveltite, native bismuth, paganoite and two undefined arsenates. Subhedral equant crystals with rounded faces are intimately intergrown in 1 mm-sized aggregates and individual grains do not exceed 0.5 mm in maximum diameter. The average crystal size is variable from 20 μm to 0.3 mm. The colour varies from dark violet-red to dark brownish-red and the streak is pale reddish-brown to pale purplish-brown. Crystals are translucent, brittle, vitreous, and do not fluoresce under ultraviolet light. The mineral shows neither twinning nor cleavage, has an uneven fracture, and the calculated density (for the empirical formula) is 4.904 g/cm3. Electron-microprobe analyses gave NiO 19.45, CoO 18.39, CuO 3.40, CaO 0.17, FeO 0.04, As2O5 60.32, total 101.77 wt.%. The empirical formula, derived from crystal-structure analysis and electron-microprobe analyses, is (Ni14.662+Co13.822+Cu2.412+Ca0.17Fe0.032+)Σ31.09(As1.975+O7)15, based on O = 105 atoms per formula unit (a.p.f.u.). In reflected plane-polarized light in air, petewilliamsite is dark grey with orange to spectral (multicoloured) internal reflections and no obvious bireflectance, anisotropy or pleochroism. Measured reflectance values in air are tabulated; the index of refraction calculated at 589 nm is 1.88. The mineral name honours Professor Peter (‘Pete’) Allan Williams of the University of Western Sydney, New South Wales, Australia, for his contributions to the study of secondary minerals.

The crystal structure of petewilliamsite has been solved by direct methods and refined on the basis of F2 using 9212 unique reflections measured with Mo-Kα X-radiation on a diffractometer equipped with a CCDbased detector. The final R1 was 7.68%, calculated for 1273 observed reflections. The structure contains 15 symmetrically distinct As5+ cations, each of which is tetrahedrally coordinated by four O atoms, and pairs of these AsO4 tetrahedra share a vertex which results in As2O7 pyroarsenate groups that are in layers parallel to (010). The structure also has 16 distinct transition-metal M (M: Ni,Co) sites of which there are one tetrahedral, four square bipyramidal, and 11 octahedral arrangements. Adjacent pyroarsenate groups are linked through bonds to M cations. The structure of petewilliamsite is not closely related to other naturally occurring arsenates and it is the first pyroarsenate mineral.

Many syntheses have been carried out in order to establish the possibility of replacing manganese in spessartine, Mn3Al2(SiO4)3, by various elements (Be, Mg, Ca, Sr, Ba, Pb, Cu, Ni, Co, Fe2+, Sc, Yt, Zn, Cd) as well as aluminium by Sc, Yt, Zr, Ti, Cr, Fe3+ by a solid state reaction. The syntheses were done by sintering pellets of the desired composition at about 1100 °C for 5–10 hours under normal pressure. It has been found that an inert atmosphere creates more favourable conditions for the syntheses of spessartine analogues, compared to the results obtained in the open-air reaction, where often spinel was obtained. All the reaction products were submitted to X-ray and chemical analysis and to IR spectroscopical examination.

Fluorine-, boron- and magnesium-rich metamorphosed xenoliths occur in the Campanian Ignimbrite deposits at Fiano (southern Italy), at ∼50 km northeast of the sourced volcanic area. These rocks originated from Mesozoic limestones of the Campanian Apennines, embedded in a fluid flow. The Fiano xenoliths studied consist of ten fluorophlogopite-bearing calc-silicate rocks and five carbonate xenoliths, characterized by combining mineralogical analyses with whole-rock and stable isotope data. The micaceous xenoliths are composed of abundant idiomorphic fluorophlogopite, widespread fluorite, F-rich chondrodite, fluoborite, diopside, Fe(Mg)-oxides, calcite, humite, K-bearing fluoro-richterite and grossular. Of the five mica-free xenoliths, two are calcite marbles, containing subordinate fluorite and hematite, and three are weakly metamorphosed carbonates, composed only of calcite. The crystal structure and composition of fluorophlogopite approach that of the end-member. The Fiano xenoliths are enriched in trace elements with respect to the primary limestones. Comparisons between the rare-earth element (REE) patterns of the Fiano xenoliths and those of both Campanian Ignimbrite and Somma-Vesuvius marble and carbonate xenoliths showthat the Fiano pattern overlaps that of Somma-Vesuvius marble and carbonate xenoliths, and reproduces the trend of Campanian Ignimbrite rocks. Values of δ13C and δ18O depict the same trend of depletion in the heavy isotopes observed in the Somma-Vesuvius nodules, and is related to thermometamorphism. Trace-element distribution, paragenesis, stable isotope geochemistry and data modelling point to infiltration of steam enriched in F, B,Mg and As into carbonate rocks at a temperature of ∼300–450°C during the emplacement of the Campanian Ignimbrite.

A review is given of the metallurgical literature relating to the formation of metal rodeutectics, which are texturally similar to myrmekite. Since no satisfactory explanation for rodeutectics has been advanced, a comparison is made with myrmekite. It is proposed that this intergrowth develops as a result of the constriction of quartz during its recrystallization and inclusion in an expanding blastic growth of plagioclase, and the forces involved lead to the prolongation along the growth directions of quartz in the form of rods with a relatively small surface area (i.e. with circular cross-sections). Possible forces that could produce the same geometry in metal intergrowths are those that result from the relative contractions of the two components during freezing; in all cases for which quantitative data are known, the metallic rods have a greater contraction on freezing than the host substance. Examples of myrmekite and myrmekite-like intergrowths in the Constant Gneiss are described in relation to their particular origin. Two factors, the lack of proportionality of qtartz to feldspar and the intimate association of myrmekite with myrmekite-like intergrowths, support the proposed mechanism of constriction of pre-existing quartz.

The crystal structure of the rare skarn mineral trabzonite, Ca4[Si3O9(OH)]OH, from the type locality near Ikizdere, Turkey and from the Upper Chegem caldera, Northern Caucasus, Kabardino-Balkaria, Russia has been solved and refined using single-crystal X-ray data. This shows that the chemical formula should be modified from Ca4(Si3O10)˙2H2O, reported in the original trabzonite description, to an OH-bearing composition. The crystal structure, which contains Si3O10 trimers embedded in a framework of CaO6–8 polyhedra, has orthorhombic symmetry, space group Ama2, a = 20.6, b = 9.1, c = 10.3 Å. The orthorhombic A-centred cell is easily obtained by transformation from the original monoclinic cell of P21/m symmetry. The revised formula means that trabzonite and foshagite are polymorphs; foshagite has wollastonite-like silicate chains and in contrast to trabzonite it does not contain silanol groups. The structure and composition of killalaite from both localities was also studied. Single-crystal X-ray structure refinement of killalaite from the Northern Caucasus confirmed it to be non-stoichiometric with a composition between Ca6[Si2O6(OH)]2(OH)2 and Ca7[Si2O7]2(OH)2(Z = 2). Trabzonite, killalaite and dellaite form a series of modular structures which differ mainly in the degree of condensation of the SiO4 units.

A single-crystal X-ray diffraction study of a sample of natural gedrite from North Carolina, USA, with the crystal-chemical formula ANa0.47B(Na0.03Mg0.97Fe0.942+Mn0.02Ca0.04)C(Mg3.52Fe0.282+Al1.15Ti0.054+)T(Si6.31Al1.69)O22W(OH)2, up to a maximum pressure of 7 GPa, revealed the following bulk and axial moduli and their pressure derivatives: K0T = 91.2(6) GPa [K0T' = 6.3(2)]; K0T(a) = 60.5(6) GPa [K0T(a)' = 6.1(2)]; K0T(b) = 122.8(2.6) GPa [K0T(b)' = 5.7(8)]; K0T (c) = 119.7(1.5) GPa [K0T(c)' = 5.1(5)]. Gedrite has a much higher bulk modulus than anthophyllite (66 GPa) and proto-amphibole (64 GPa). All of the three axial moduli of gedrite are higher than those of these two other orthoamphiboles. The greater stiffness of gedrite along [100] is due to its high ANa content, which is almost zero in anthophyllite and proto-amphibole. The much greater stiffness parallel to the (100) plane of gedrite compared with the two other amphiboles is probably due to its high CAl content. A comparison is made with published data available for orthorhombic B(Mg, Mn, Fe) and monoclinic BCa amphiboles to identify correlations between crystal-chemistry and compressibility in amphiboles.

Microprobe analysis of marshite and miersite from Broken Hill, Australia, demonstrate extensive solid solution between the end-members CuI and AgI, indicating the possibility of a complete solid-solution series. Unit-cell parameters increase from 6.054 Å for marshite to 6.504 Å for miersite, closely following Vegard's Law. The Cu content of iodargyrite is generally below the limit of detection, but one zoned crystal contained 0.28 wt.% Cu. Crystallization of either miersite or iodargyrite at Broken Hill appears to be dependent upon the local availability and ratio of copper, silver and iodine ions.

New Pd-Tl-(Bi,As)-rich compounds are described from the Anomal'nyi Cu-PGE deposit, Kondyor alkaline ultramafic complex, northeastern Russia. They occur in vein-type settings associated with bodies of 'kosvite' (magnetite-rich clinopyroxenite) in the dunite-(peridotite) core, in pegmatiticand micaceous rocks. The ore zones are substantially enriched in phlogopite; they consist of diopside, disseminated titaniferous magnetite and fluorapatite (Sr-bearing). The observed assemblages of ore minerals include sulfides of the chalcopyrite-bornite-(secondary chalcocite) associationand various species of platinum-group minerals (PGM) [isomertieite or arsenopalladinite rich in Sb, mertieite-II, mertieite-I, sobolevskite, kotulskite, merenskyite, zvyagintsevite, palarstanide, paolovite, sperrylite, maslovite or moncheite, hollingworthite and unnamed species of PGM] anda Ag-Au alloy. The oxides [Pd4(Bi,Te,Tl)O6 and Pd4(Tl,Bi,Te)O6] probably formed in situ by oxidation reactions at the expense of the associated PGM intergrowths. These involve palladium bismuthide-thallide phases, Pd5(Tl,As,Bi)and Pd5(As,Tl,Bi), which are documented here for the first time. A fairly evolved environment, enriched in Cu, Pd, Te, Bi, Pb and volatile components, is indicated for the vein-type deposit at Anomal'nyi.

This study presents a complete characterization of kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], occurring in an amazonite pegmatite from Ploskaya Mountain, Western Keivy Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia.

Kenoplumbomicrolite occurs in yellowish brown octahedral, cuboctahedral and massive crystals, up to 20 cm, has a white streak, a greasy lustre and is translucent. The Mohs hardness is ~6. Attempts to measure density (7.310–7.832 g/cm3) were affected by the ubiquitous presence of uraninite inclusions. Reflectance values were measured in air and immersed in oil. Kenoplumbocrolite is optically isotropic. The empirical formula is (Pb1.30□0.30Ca0.29Na0.08U0.03)Σ2.00(Ta0.82Nb0.62Si0.23Sn4+0.15Ti0.07Fe3+0.10Al0.01)Σ2.00O6[□0.52(OH)0.25O0.23]Σ1.00 (from the crystal used for the structural study) and (Pb1.33□0.66Mn0.01)Σ2.00(Ta0.87Nb0.72Sn4+0.18Fe3+0.11W0.08Ti0.04)Σ2.00O6[□0.80(OH)0.10O0.10]Σ1.00 (average including additional fragments). The mineral is cubic, space group Fd$\overline 3 $m. The unit-cell parameters refined from powder X-ray diffraction data are a = 10.575(2) Å and V = 1182.6(8) Å3, which are in accord with those obtained previously from a single crystal of a = 10.571(1) Å, V = 1181.3(2) Å3 and Z = 8. The mineral description and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2015-007a).

The manganese ores of the Benallt mine are pervaded by an orange-coloured mineral which occurs very poorly crystallized as patches and small specks in the matrix. Less commonly it occurs as minute flakes in the ore and sometimes as a constituent of very thin veins which traverse the ore. In some specimens the mineral is better developed. It then shows a good cleavage and resembles in appearance in thin section a weakly pleochroic mica or chlorite. Patches of this mineral in the matrix frequently enclose very small rounded garnets which are believed to be spessartine.

In 1932 Dr. A. F. Hallimond examined some sections of ore from the old Benallt mine for Dr. C. A. Matley and suggested that one of the constituent minerals might be a manganiferous chlorite.