Vymazalováite, Pd3Bi2S2 is a new platinum-group mineral discovered in the Komsomolsky mine of the Talnakh deposit, Noril'sk district, Russia. It forms small (from a few μm to 20–35 µm) inclusions or euhedral grains in intergrowths of polarite, sobolevskite, acanthite and unnamed (Pd,Ag)5BiS2 in aggregates (up to ~200 µm) in galena and rarely in chalcopyrite. It occurs with telargpalite, cooperite, braggite, vysotskite, sopcheite, stibiopalladinite, sobolevskite, moncheite, kotulskite, malyshevite, insizwaite, Au-bearing silver and the newly described mineral kravtsovite (PdAg2S) in association with pyrite, chalcopyrite and galena in vein-disseminated mineralization in skarn rocks. Synthetic vymazalováite is brittle; it has a metallic lustre and a grey streak. In plane-polarized reflected light, vymazalováite is creamy grey and appears slightly brownish against galena in the assemblage with chalcopyrite. It exhibits no internal reflections. Average reflectance values in air for natural and synthetic vymazalováite are (R natural, R synthetic in %) are: 46.35, 45.7 at 470 nm, 47.65, 47.45 at 546 nm, 48.5, 48.2 at 589 nm and 49.5, 49.0 at 650 nm. Seven electron probe micro-analyses of vymazalováite give an average composition: Pd 40.42, Bi 49.15, Ag 0.55, Pb 1.02, S 7.77 and Se 0.26, total 99.17 wt.%, corresponding to the empirical formula Pd3.05(Bi1.89Ag0.04Pb0.04)Σ1.97(S1.95Se0.03)Σ1.98 based on a total of 7 atoms per formula unit. The simplified formula is Pd3Bi2S2. The mineral is cubic, space group I213, with a = 8.3097(9) Å, V = 573.79(1) Å3 and Z = 4. The density calculated on the basis of the empirical formula and cell dimensions of synthetic vymazalováite is 9.25 g/cm3. The strongest lines in the powder X-ray diffraction pattern of synthetic vymazalováite [d in Å (I) (hkl)] are: 4.15(32)(200), 2.93(78)(220), 2.40(100)(220), 2.08(53)(400), 1.695(34)(422), 1.468(35)(440) and 1.252(31)(622). The structural identity of natural vymazalováite with synthetic Pd3Bi2S2 was confirmed by electron back-scatter diffraction measurements on the natural sample. This new mineral honours Dr Anna Vymazalová of the Czech Geological Survey, Prague.

The mass suseeptibility of 23 analysed or partially analysed garnets has been measured by means of a calibrated Franz Isodynamic magnetic separator. Straight lines are fitted to the adjusted data for mass susceptibility and molecular composition. The mass susceptibilities of the theoretical end-members in electromagnetic units × 106 are estimated as: almandine, 68±2 e.m.u.; spessartine, 81±3 e.m.u.; and andradite, 49±3 e.m.u. Grossular and pyrope are assumed to have susceptibilities of nil.

A new variety of garnet, a chromian hydrogrossular, has been found in a loose block of diopside-albite rock in a quarry of serpentinite in Jordanów, Lower Silesia. Its chemical formula is given. Although the water content of this garnet barely exceeds 1 %, the X-ray, thermal, infra-red spectrophotometric, and optical examinations give evidence that this water, in the form of (OH)4 groupings, substitutes for the SiO4 tetrahedra. The chromian hydrogrossular from Jordanów belongs to the numerous calcium-rich silicates that were formed there during the process of alteration of serpentinites by lime-rich hydrothermal solutions.

A new data analysis toolkit which is suitable for the analysis of large-scale, long-term datasets and the phenomenon/anomalies they represent is described. The toolkit aims to expose and quantify scientific information in a number of forms contained within a time-series based dataset in a quantitative and rigorous manner, reducing the subjectivity of observations made, thereby supporting the scientific observer. The features contained within the toolkit include the ability to handle non-uniform datasets, time-series component determination, frequency component determination, feature/event detection and characterization/parameterization of local behaviours. An application is presented of a case study dataset arising from the 'Lasgit' experiment.

Trace element variations in stream sediments from an area of 76 000 km2 in central Colorado are used to identify uraniferous granitoids on the basis of whole rock geochemical criteria developed to distinguish barren from metalliferous granitoids in Britain. These criteria (which include enhanced Ba, Be, Cs, Cs/Ba, K, La/Eu, Li, Lu/Eu, Nb, Rb, Rb/K, low Sr and Mg, and RE patterns with marked negative Eu anomalies) are used to formulate an index based on the Pikes Peak batholith of the Front Range as a type uranium source rock.

Uraniferous granitoids in Colorado, which are associated with sedimentary basins containing major uranium mineralization, are identified using this index which may be applicable to the interpretation of stream sediments from elsewhere. The use of stream sediment geochemistry as an exploration method for similar uranium source rocks, which may indicate potential uranium provinces, is thus possible.

Spinel lherzolite xenoliths from two localities in the Massif Central are undepleted in Al2O3, CaO, and Na2O. One suite from Tarreyres, is K2O depleted and amphibole-bearing whereas the other, from Monistrol d'Allier some 18 km away, is amphibole-free and has a higher mean K2O content of 0.035 wt.%. We present bulk major and minor element abundances in a harzburgite and a lherzolite from each locality and microprobe analyses of their constituent phases. Amphibole-bearing lherzolite and its pyroxenes are light-rare earth element (LREE) depleted, whereas amphibole-free lherzolite and its pyroxenes are LREE enriched. Both harzburgites and their pyroxenes are LREE enriched and one rock contains LREE enriched glass. The harzburgites are like harzburgite xenoliths from elsewhere but each lherzolite represents a previously unrecognized type of mantle in terms of the mineralogy and REE content. The implication for basalt genesis are briefly discussed.

The crystal structures of a suite of amphiboles from the Kola Superdeep Borehole, Russia, have been refined to R values of ∼3% using single-crystal Mo-Kα X-ray diffraction data. The same crystals used in the collection of the intensity data were subsequently analysed by electron microprobe (EMP) and milliprobe Mössbauer spectroscopy. Site populations were assigned from the results of site-scattering refinement and stereochemical analysis, taking into account the unit formula determined for each crystal. The Fe3+/(Fe2++Fe3+) values were derived (1) by least-squares refinement of the Mössbauer spectra, and (2) SREF (Structure REFinement) by careful analysis of the mean bond lengths at the M(2) site using two possible models for the behaviour of Ti4+: (i) Ti4+ at M(2); and (ii) Ti4+ at M(1). The agreement between the SREF and Mössbauer/EMP values for Fe3+ is very close for Ti4+ assigned to M(2). This result indicates that the calculation of Fe3+ contents in amphiboles from refined site populations and <M(2)–O> distances are accurate. This paper presents the first confirmation of this result.

The [4]Al/Si and [6]Al/Mg order-disorder behaviour of minerals in the tremolite-tschermakite solid solution (namely, end-member tschermakite and the 50:50 composition, magnesiohornblende) has been investigated by Monte Carlo simulation, using a model Hamiltonian in which atomic interaction parameters Ji were derived from empirical lattice energy calculations, and chemical potential terms μj (to express the preferences of cations for particular crystallographic sites) were derived from ab initio methods. The simulations performed were increasingly complex. Firstly, ordering in one tetrahedral double chain with Al:Si = 1:3 (tschermakite) was simulated. Although the low-temperature cation distribution in this system was ordered, there was no phase transition (due to the quasi-one-dimensional nature of the system). Next, interactions between tetrahedral Al:Si = 1:3 double chains were included, and a phase transition was observed, with the cation distribution in one double chain lining up with respect to that in the next. Finally, interactions between tetrahedral and octahedral sites were incorporated, to model the whole unit cell, and compositions corresponding to tschermakite and magnesiohornblende were investigated. The whole-cell simulation results compare favourably with experimental conclusions for magnesiohornblende, in that Al at T1 is preferred over Al at T2, and Al at M2 is favoured over that at M1 and M3, but the significant amount of Al at M1 is at odds with experimental observation.

The heat capacity of synthetic lazulite, MgAl2(PO4)2(OH)2, has been measured between 35 and 298 K by means of low-temperature adiabatic calorimetry. A lazulite third-law entropy (S2980) value of 204(3) J K–1 mol–1 was retrieved after extrapolation of the lazulite heat capacity by a cubic temperature function, down to absolute temperature. Identical measurements on α-Al2O3 yielded S2980 = 51.2 J mol–1 K–1 instead of the recommended 50.94 J mol–1 K–1 value. This new lazulite third-law entropy along with other phosphate entropy data either derived from low-temperature adiabatic calorimetry or experimental phase equilibria under pressure and temperature, were computed to retrieve a (S–V)P2O5 value of 57.4(2.9) to predict phosphate entropies from oxide summation. The predicted third-law entropy for trolleite, Al4(PO4)3(OH)3, amounts to 285.4(8.5) J mol–1 K–1 ~13% higher than the previously published value. We propose a new formation enthalpy from the elements of –6504.2 kJ mol–1 and a new third-law entropy of 281.7 J mol–1 K–1 for trolleite, compatible with the predicted entropy from oxide summation as well as with the published brackets on the trolleite = berlinite + corundum + water reaction.

Agates with spectacular micro-structural features were found in volcanic rocks at several occurrences in the Saar-Nahe region (Germany). These agates include spirals of several tens up to several hundreds of μm in size within zones lacking the characteristic structural agate banding. A combined mineralogical study by polarising microscopy, scanning electron microscopy, cathodoluminescence microscopy and spectroscopy, and electron backscatter diffraction provided evidence that the spirals consist of well-ordered trigonal α-quartz, whereas the surrounding matrix is composed of strongly disordered or amorphous SiO2 phases. The quartz micro-crystals show a systematic rotation of the crystal orientation perpendicular to the direction of the spiral loops indicating helical growth.

It is assumed that the spiral growth is initiated by dislocations with a screw component. The lacking symmetry of the strongly disordered or amorphous matrix initiated a curved development by a screw dislocation in a system far from equilibrium. The atoms/molecules are packed into spiral layers, which is energetically favoured in comparison with the incorporation into plane crystal faces. Such self-organisation growth and polymerisation initiated by a screw dislocation can produce variable spiral morphologies sometimes resembling living forms.

Variation in composition, Fe3+/Fe2+ ratio, per cent mixed-layering, and d(060) spacing have been determined both between and within grains of glauconite from the Folkestone Beds at 286.5 m in the Tollgate bore, Sandwich, Kent. Grains extracted from the rock were classified on the basis of size into large (> 1 mm) and small (< 1 mm), and on colour into light and dark green. Large grains have a progressive increase in Fe3+/Fe2+ ratio with increase in total iron, while small grains have variable ratios; the largest variation is in the dark grains. The effect of the range of Fe3+/Fe2+ ratio variations on structural formula (e.g. R3+) is discussed. The per cent mixed-layering is not related to colour. There is a greater variation in Al, Fe, and K contents in and between large grains than small grains. Both sizes of grains may be separated on d(060) spacings determined by X-ray diffraction. Glauconite from coral and gastropod casts has different d(060) spacings than that from bryozoan casts and variegated grains, but is similar to the small grains. Large light grains may have developed from small light grains but it is unlikely that the large dark grains developed from small dark grains. The large grains probably all formed under similar conditions, with a common origin; the small from several sources or from a single source under a variety of conditions.

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.

Caratiite is a sulphate-chloride of potassium and copper with ideal formula K4Cu4O2(SO4)4MeCl (where Me = Na and/or Cu); it formed as fine green acicular crystals in lava of the 1869 eruption of Mt. Vesuvius, Naples, Italy. Caratiite is tetragonal, space group I4; a 13.60(2), c 4.98(1) Å, Z = 2. The strongest lines of the powder pattern are [d Å, I, hkl]: 9.61 100 (110); 6.80 80 (200); 4.296 60 (310); 3.015 100b (420,321); 2.747 70 (411); 2.673 60 (510); 2.478 60 (002); 2.388 70 (431,501); 2.281 60 (600). The mineral is uniaxial positive, ω 1.598, ɛ 1.711; it does not fluoresce under either short- or long-wavelength ultra-violet light. The specific gravity is 3.0 (meas.) and 3.22 (calc.).

Minohlite, a new copper-zinc sulfate mineral related to schulenbergite, was found in the oxidized zone of the Hirao mine at Minoh (Minoo) City, Osaka Prefecture, Japan. The mineral occurs in cracks in altered shale as rosette aggregates up to 100 m m in diameter, composed of hexagonal platy crystals up to 50 μm m in diameter and 10 μm m in thickness. The associated minerals are chamosite, muscovite, smithsonite, serpierite, ramsbeckite, 'limonite' and chalcopyrite. Minohlite has hexagonal (or trigonal) symmetry with unit-cell parameters of a = 8.2535(11), c = 8.1352(17) Å, V = 479.93(16) Å3 and Z = 1, and possible space groups P6, P, P6/m, P22, P6mm, P2m and P6/mmm (or P3, P3, P321, P3m1, Pm1, P312, P31m and P1m). The six strongest reflections in the powder X-ray diffraction pattern [d in Å (I) hkl] are 8.138 (20) 001; 4.128 (24) 110; 2.702 (100) 120; 2.564 (76) 121; 1.560 (43) 140; and 1.532 (24) 141. Electron microprobe analyses gave the following values (wt.%): CuO 37.18, ZnO 21.08, FeO 0.49, SO3 16.78, SiO2 0.44, and H2O 24.03 (by difference). The empirical formula, calculated on the basis of Cu + Zn + Fe + S + Si = 9 atoms per formula unit, is (Cu4.43Zn2.45Fe0.06)Σ6.94[(SO4)1.99(SiO4)0.07]Σ2.06(OH)9.64·7.81H2O, which leads a simplified formula of (Cu,Zn)7(SO4)2(OH)10·8H2O where Cu > Zn. The mineral is bluish-green and transparent with a pearly to vitreous lustre. The streak is pale green. Cleavage is perfect on {001}. The Mohs hardness number is less than 2. The calculated density is 3.28 g cm−3. The mineral is named after Minoh City, where it was discovered.

The crystallographic orientation of carlsbergite (CrN) in the north Chile meteorite (hexahedrite) was investigated using electron backscatter diffraction and transmission electron microscopy. These studies examined the CrN crystals in the rhabdites (idiomorphic schreibersite) and in kamacite. It was found that the CrN crystals embedded in rhabdite show a number of different orientation relationships with the host crystals. These orientations can be explained based on the lattice dimensions of both coexisting crystalline materials. It was also found that both carlsbergite and kamacite are characterized by a high dislocation density (≥ l09 cm-2) while rhabdite is free of dislocations. It is supposed that in spite of the deformed metallic matrix, a general connection between the orientation relation of all the phases involved exists.

Hydrothermal uranium veins, associated with the Hercynian leucogranites show important variations in their mineralogical, chemical and structural features in relation to the host rock lithology. These are described with particular reference to the Chardon deposit, Vendée where the veins cut granite, basic lithologies, and shales. The following features are described:

1. 1 Changes in the thickness of veins near to contact zones, particularly those between granites and basic lithologies, lamprophyres, and shales.

2. 2 Changes in the gangue mineral assemblage with the preferential development of carbonate in veins cutting basic lithologies, and of silica in veins which cut granite.

3. 3 Paragenetic zoning in the veins in passing from granites to their metamorphic aureoles.

Comparisons between deposits of Vendée, Limousin, and Erzgebirge allow the following generalizations to be made:

1. 1 Open faults and subsequent mineralization are concentrated at boundaries between competent and more plastic lithologies.

2. 2 Mineralizing fluids cause wall-rock alteration characterized by the removal of Si from granite and of Ca, Mg, Fe from metamorphic and basic rocks.

3. 3 The chemical and structural characteristics of wallrocks are important controls on the mineralization but in acid lithologies the main controls on the pitchblende vein formation are the structural characteristics of the wallrock.

The Currywongaun and Doughruagh masses of northern Connemara represent a section through a syntectonic, partially layered intrusion formed of ultrabasic cumulates all having plagioclase of around An94. Differentiation and contamination of the magma from which these cumulates were precipitated ultimately produced an acid residuum which was responsible for the hydrous metasomatism of the earlier formed ultrabasic rocks resulting in the extensive formation of quartz-amphibole-anorthite gneisses in the petrogenetically ‘upper’ parts of the intrusion. Coexisting Ca-rich and Ca-poor amphiboles in the gneisses are interpreted as ‘frozen’ reaction intermediates that were in local equilibrium. The bulk-rock chemical data presented confirm that the compositions of the quartz-rich gneisses can be attributed almost entirely to the addition of Si to the ultrabasic rocks, coupled with the removal of Mg and Ca. The data also suggest that Zr, which reaches around 1000 ppm in some of the gneisses, may have been ‘mobile’ under these conditions of hydrothermal metasomatism.