Cathodoluminescence (CL) provides a sensitive analytical probe of the near-surface region of insulating materials, and some new examples of the strengths of the technique are presented using recent data from the University of Sussex. Analysis of float glass shows that by spectral and lifetime resolved data it is possible to separate the emission bands from excitonic, intrinsic imperfections, and impurities in various valence states, as a function of their depth beneath the surface. Correlation of the CL data with those from Mössbauer, ion beam and other analyses then provides the basis for models of the defect sites. CL from a second glass, ZBLAN, reveals the presence of microcrystallites and growth defects, and the work underpins confidence in the high purity gas levitation method of ZBLAN production. New results on CL of wavelength shifts with crystal field of Mn in carbonates are presented, and of Nd emission from Nd:YAG. The effects are directly linked to surface damage and dislocations caused by sample preparation steps of cutting and polishing. Methods to minimise the damage, by furnace or pulsed laser annealing, and chemical routes, are mentioned. Such surface preparation damage has a profound effect on all CL monitoring, whether for fundamental studies or mineralogical applications. Finally, a route to eliminate such problems is demonstrated, with consequent improvements in luminescence, transmission and laser performance of surface waveguides. The implications of improved surface quality range widely from mineralogical CL imaging through improved photonic materials and epitaxial growth to elimination of surface damage, and additional information.

Pegmatites of the Fregeneda area, Salamanca, Spain, show a zonal distribution, from barren to enrichment in Li, Sn, Rb, Nb>Ta, B and P. They intrude pre-Ordovician metasediments which were metamorphosed to sillimanite-zone conditions near the Lumbrales granite. Field, mineralogical and petrographic data show the following zonal sequence from the granite outward: (1) barren pegmatites (pegmatites T1, T2, T3 and T4) with quartz, K-feldspar > albite, muscovite, tourmaline ± andalusite ± garnet; (2) intermediate pegmatites (types T5 and T6), characterized by the occurrence of beryl and Fe-Mn-Li phosphates; and (3) fertile pegmatites (dykes T7 and T8), with lepidolite, cassiterite, columbite, albite > K-feldspar, montebrasite and spodumene.

Tourmaline from different pegmatites shows significant compositional variations. Trace element variations in mica and K-feldspar suggest that the origin of the different pegmatitic bodies may be explained by three different paths of fractional crystallization of melts generated by partial melting of quartzo-feldspathic rocks.

The oxidation of chalcopyrite and pyrite was examined using Fe-K- and Cu-K-edge REFLEXAFS spectroscopy. The Fe XANES of the pyrite proved to be a very sensitive indicator of oxidation, revealing the development of a goethite-like surface species; the EXAFS data showed an increasing O:S ratio with the degree of oxidation and gave Fe–O distances of c. 1.9 Å. On the oxidized chalcopyrite surfaces, the development of Fe-O and Cu-O species was observed, with both the XANES and EXAFS revealing the progressive development of these species with oxidation. Differences in the sensitivity of the XANES and EXAFS to the degree of oxidation can be related to the degree of long range order and changes in the intensity of the pre-edge feature of the Fe are a function of its oxidation state and coordination geometry in the surface species.

Pd-rich PGM (platinum-group minerals) have been found in sulphide-bearing dunites and harzburgites from the Inazumi-yama ultramafic complex in southwestern Japan. In the dunite, potarite (PdHg0.85–0.88) is the most abundant PGM but other associated PGM include stibiopalladinite (Pd5Sb2) and rare sperrylite (PtAs2) and Pd-rich alloys. A Pd telluride has been found in the harzburgite. The PGM are enclosed usually by pentlandite-heazlewoodite composite grains and, rarely, by altered chrome-spinel. These minerals are characteristic of an ultramafic assemblage but they are accompanied by ubiquitous galena and minor sphalerite not usually associated with these ultramafic assemblages. The ultramafic part of this complex has been thermally metamorphosed (olivine-talc zone) within the contact aureole of an adjacent granite. The PGM, sulphides and altered spinel are all intergrown with antigorite and/or chlorite, indicating a metamorphic overprint on the primary igneous mineralogy. The Pd/Pt ratios of 9 suggest a process of hydrothermal concentration for the Pd and it is proposed that the Pd has been remobilized and reconcentrated by hydrothermal solutions derived from the granitic magma which reacted with the Pd concentrated in the primary magmatic sulphides. Mercury may have been leached from surrounding sediments by the hydrothermal solutions. It is possible that potarite and the other PGM formed at temperatures of up to 650°C and are likely to be found in other thermally metamorphosed ultramafic rocks showing a depleted character (spinel Cr/[Cr+Al]>0.7), common in orogenic belts.

Thallium leucite, TlAlSi2O6, has been synthesized at 450°C for 7 days, under ambient conditions, by the transformation of dehydrated analcime NaAlSi2O6 in the presence of excess TlCl. This substitution of Tl for Na leads to confirmation of a thallium-leucite pseudomorph after analcime. Their optical properties, X-ray powder diffraction patterns, electron microprobe analysis, infrared spectra, and X-ray photoelectron spectroscopy have characterized the synthetic Tl-leucites. The IR spectra show that the mid-IR modes T-O stretching and T-O-T bending vibrations for TlAlSi2O6 are more resemblant of those for analcime than for leucite, KAlSi2O6. This resemblance implies that Tl cation enters the W-site rather than the S-site in the analcime structure: Na (S) + H2O (W) ⇋ □ + K (leucite) ⇋ □ + Tl (Tl- leucite), where □ represents an S-site vacancy. The mechanism of this substitution is supported by the crystal chemical constraints: inasmuch as the S-site is smaller than the W-site, Tl+ cations being larger than Na+ plainly prefer the latter site to the former. One inference from the binding energy for Tl+ by XPS is that Tl+ occupies the extra-framework site in synthetic leucite pseudomorph, rather than the smaller tetrahedral site. The difference in Al/Si disordering between analcime and leucite and the nonstoichiometry due to the solid solution of the □Si3O6 component into the leucite structure may provide a fundamental insight into understanding why TlAlSi2O6 deviates from the trend defined by K-, Rb- and CsAlSi2O6 leucite series on the a-c parameter diagram, inasmuch as these three cations in the leucite structure occupy the W-sites. Finally, synthesis of TlAlSi2O6 leucite has an implication for the existence of other polymorphs due to different degrees of Al/Si disordering, except for high- and low-temperature leucites already known: natural leucites crystallized directly through igneous processes are different from those formed by substitution of K for Na in analcimes.

Pumpellyite has been found in doleritic basalt of a sheeted dyke complex drilled from 2072.1 m below sea floor in DSDP/ODP Hole 504B, south of the Costa Rica Rift, eastern Pacific. It occurs as fine-grained crystal aggregates accompanied by albite, chlorite and chalcopyrite, which partially replace a plagioclase phenocryst (An85–88) that is also associated with primary magnetite. Chemical compositions of the pumpellyite vary antithetically in relation to Fe* and Al as well as Fe* and Mg, indicating the dominant substitution of Fe3+ by Al with the minor substitution of Fe2+ by Mg. Such compositional variations overlap with those of prehnite-pumpellyite facies rocks dredged from other oceanic ridges and intra-oceanic arcs, and those of similar facies rocks from ophiolites, but are aluminous compared with those of zeolite facies metabasites in ophiolites. These observations suggest that the breakdown of the plagioclase phenocryst and magnetite in the presence of a Cu- and S-bearing fluid phase led to the formation of pumpellyite + albite + chlorite + chalcopyrite during oceanic ridge hydrothermal alteration.

Alkaline lamprophyre intrusives from the western Deccan Traps (Murud-Janjira, south of Bombay) host rare lithospheric xenoliths and megacrysts. The xenolith suite consists of clinopyroxenites and granulites which show eclogitic affinities. The former have transitional (porphyroclastic to equigranular) textures whereas the latter are porphyroclastic, xenomorphic to meta-igneous. The textural features provide evidence of ductile-brittle deformation. The protoliths of the pyroxenite and granulite xenoliths were formed as cumulates of alkaline and sub-alkaline magmas respectively.

Mineral chemistry and geochemical data for the xenoliths bear testimony to the metasomatized nature of the deep crust. The xenolith data coupled with the geophysical evidence indicate that the lower crust beneath Murud-Janjira is dominated by mafic granulites and pyroxenites. The latter have under- and intra-plated the continental crust beneath the region.

Detailed electron-microprobe line profiles and small-area compositional maps of zoned garnets in a sample of high-pressure-high-temperature granulite show features inconsistent with commonly applied diffusion models. Larger grains of an early garnet generation have their highest Ca contents in domains away from the rim or inclusions but show a sharp fall in Ca balanced by increased Mg and Fe (and slightly higher XMg) towards inclusions and the rim. In domains with secondary biotite, the sharp decrease in Ca is accompanied by variations in XMg dependent upon proximity to biotite, thus producing one-sided, asymmetric profiles with XMg lower against biotite. As a consequence, rim compositions of the same grain are different on the sides adjacent and away from biotite and there is no relationship between grain size and rim XMg. Such a zoning pattern requires that grain-boundary diffusion is as slow as volume diffusion and implies the absence of a diffusion-enhancing grain-boundary fluid phase during the majority of the rock's high-temperature exhumation history. Diffusion models ignoring this probability could yield either cooling rates that were too fast, or extrapolated ages based on closure temperature models that were too old.

A second garnet generation in the same rock, grown in a Ca-rich domain resulting from kyanite breakdown, has irregularly distributed patches, identified by compositional mapping, containing higher Ca than the first-formed garnet but at lower XMg. Use of such garnet compositions for geothermobarometrical determination of the high-pressure granulite stage would clearly lead to erroneous results. The presence of such contrasting garnet compositions in a granulite-facies rock is clearly evidence of disequilibrium, and further supports the proposition that there was a lack of an effective transport medium even at the mm scale.

In this paper we present new petrological and geochemical data for two peraluminous granite batholiths (Nisa Alburquerque and Jalama batholiths) representative of the ‘Araya-type’ granites of the Central-Iberian Zone. Both granites are composite with several facies (monzogranites and leucogranites) that can be grouped into two main granite units: the external units and central units. Intrusive relationships and lack of geochemical coherence between the central and external units indicate that they are not comagmatic but represent different pulses. The central units of both batholiths are petrologically and geochemically different. On the other hand, external units show a lot of similarities and are the main object of this study. The main characteristics of the external granites can be interpreted in terms of an incomplete fractional crystallization process of early mineral phases (plg + Kf + bt) which probably took place at the level of emplacement. Other possible mechanisms of magmatic differentiation (magma mixing, restite unmixing, sequential melting) can be discarded based on field, petrography and geochemical data. We propose that the ‘Araya-type’ granites are formed by the intrusion of distinct magma pulses (central and external). Further evolution within each pulse can be due to incomplete fractional crystallization possibly taking place at the emplacement level.

The crystal structure of barstowite (3PbCl2·PbCO3·H2O, P21/m, a = 4.2023(5), b = 9.2020(7), c = 16.6608(6)(Å), β = 91.829(9)°) from Bounds Cliff, St Endellion, Cornwall, has been determined to an R = 0.036. The structure can be described in terms of three layers stacked along [001] in the sequence …CACBCACBC… to give a 16.7 Å repeat. Layer A consists of face-sharing PbCl8 distorted square antiprisms. Layer B is composed of Pb coordinated to 5 Cl and 2 O each with two H to form H2O groups. Layer C is formed by Pb coordinated to 5 Cl and 3 O which are from CO3 groups. The H positions are deduced and are H-bonded to O from carbonates. The structural details were in agreement with previous deductions based on infrared spectra.

Fresh and weathered pyrochlore from the Lueshe carbonatite complex (in the northeast of the Democratic Republic of Congo) was studied by Fourier transfom infrared (FTIR) spectroscopy and by a combination of FTIR spectroscopy and thermal analysis. The former was carried out in the spectral range 400–4000 cm−1. The spectra for fresh and weathered pyrochlores were very different. For the weathered pyrochlore, two bands were identified as OH vibration modes, one broad band with a maximum at 3413 cm−1 and another finer band at 1630 cm−1. The fresh pyrochlore does not show OH absorption bands. The presence of OH confirms the hydrated state of the weathered pyrochlore suggested by previous microanalytical work. The combination of FTIR spectroscopy and thermal analysis allows ‘real-time’ observation of gas emanations and solid-state transformations taking place during heating up to 800°C. For fresh pyrochlore, no solid transformation was detected, except a CO2 emanation from 242–576°C. For the weathered pyrochlore a dehydration was observed between 234–565°C followed by an exothermic peak in Differential Scanning Calorimetric (DSC) curve at 604°C. This exothermic peak corresponds to the formation of a Nb oxide phase. At higher temperatures the weathered pyrochlore is partly decomposed, forming a dehydrated pyrochlore and a Nb oxide phase. The combination of FTIR and thermal analysis has provided useful information on both fresh and weathered pyrochlore transformations which has clarified our understanding of the water control of the structural stability of pyrochlore minerals.

Experimental brackets (300–450°C) on Sb-Bi partitioning between stibnite-bismuthinites (Sb,Bi)2S3 and sulfosalts in the AgSbS2–AgBiS2 binary subsystem (α-Ag(Sb,Bi)S2, β-Ag5(Sb,Bi)4I(Sb,Bi)IIS10) and extant constraints are used to define mixing properties and standard state Gibbs energies of Sb-Bi exchange reactions. They are also used to construct a phase diagram for Ag(Sb,Bi)S2 sulfosalts. We infer that the non-ideality associated with Sb-Bi mixing is largest in minerals of the β-Ag5(Sb,Bi)4I(Sb,Bi)IIS10 series, and is sufficient to produce miscibility gaps between an ordered intermediate species Ag5(Sb)4I(Bi)IIS10 and Sb- and Bi-end-members at T < 240°C (measured in terms of symmetric regular-solution-type parameters ¼WBi−SbIβ = WBi−SbIIβ ∼ 8.5 kJ/gfw). The non-ideality associated with the Sb-Bi substitution in stibnite-bismuthinite and α-Ag(Sb,Bi)S2 is ≈ 70% that in the Ag5(Sb,Bi)4I(Sb,Bi)IIS10 series (WBi−SbBS ≈ 12.0 kJ/gfw; WBi−Sbα ≈ 6.0 kJ/gfw). It is insufficient to produce exsolution at temperatures of ore deposition (T > Tc ≈ 88°C), but most likely is responsible for a preponderance in molar Sb/Bi ratios towards end-member compositions. Finally, positive Gibbs energies of the Sb-Bi exchange reactions and indicate that Bi is more compatible in stibnite-bismuthinite sulfides than in Ag(Sb,Bi)S2 sulfosalts.

Phase relations in the dry condensed Fe-Ir-S system were determined at 1100, 1000 and 800°C. Orientational runs were performed at 500°C. Between 1100 and 800°C, the system comprises five sulphides and an uninterrupted field of γ(Fe,Ir). Fe1-xS dissolves 5.8 at.% Ir at 1100°C, 3.4 at.% Ir at 1000°C and 1.0 at.% Ir at 800°C. The solubility of Fe in Ir2S3, IrS2 and IrS~3 increases with decreasing temperature, reaching 2.5 at.% in the latter two sulphides at 800°C. Thiospinel ‘FeIr2S4— is non-stoichiometric, from Fe22.3Ir19.8S58.0 to Fe18.9Ir23.1S58.0, depending on aS and aFe, i.e. on a phase association. Thiospinel is absent at 800 and 500°C.

Uraninite is widespread as an accessory mineral in the Erzgebirge granites. It occurs throughout the entire comagmatic series of strongly peraluminous S-type Li-mica granites and has been discovered in more evolved transitional I-S type biotite and two-mica granites, but is rare in those of A-type affinity. Textural relationships and chemical ages imply that uraninite is of magmatic origin. Its composition is variable with a proportion of U plus radiogenic Pb between 71 and 99 mol.%. Uraninite has incorporated Th, Y, and the REE in total amounts between 1 and 29 mol.%. Elements such as P, Si, Al, Ca, and Fe are subordinate. Uraninite from two-mica and Li-mica granites is low in ThO2 (0.8–6.5 wt.%), Y2O3 (0–0.8 wt.%) and REE2O3 (0.1–0.6 wt.%). In contrast, biotite granites from the Kirchberg pluton contain uraninite which is enriched in these components (in wt.%) (ThO2 = 5.6–11.0, Y2O3 = 0.6–5.5, Ce2O3 = 0.1–0.6, Dy2O3 = 0.2–1.1). Commonly, the lanthanide and actinide contents in uraninite correlate poorly with those in the host granite. In S-type Li-mica granites as well as fractionated two-mica and biotite granites, uraninite is the dominant contributor to the bulk-rock U content. Here the proportion of U approaches 80–90%.

Itoigawaite, SrAl2Si2O7(OH)2·H2O, is a new member of the lawsonite group found in the Itoigawa-Ohmi district, central Japan. It is orthorhombic, Cmcm, a = 6.031(2), b = 8.945(2), c = 13.219(4) Å, Z = 4. The strongest lines in the X-ray powder diffraction pattern are 4.68 (s) (111), 4.26 (vs) (021), 3.31 (vs) (113), 2.75 (vs) (114, 202), 2.68 (vvs) (130), 2.63 (s) (131), 2.50 (s) (220, 203, 132), 2.45 (s) (221). Electron microprobe analysis gave SiO2 32.98, TiO2 0.87, Al2O3 27.67, Fe2O3 0.39, MgO 0.27, CaO 0.45, SrO 27.71, H2O (diff.) 9.66, total 100.00 wt.%, corresponding to (Sr0.97Ca0.03Mg0.02)Σ1.02 (Al1.97Ti0.04Fe0.02)Σ2.03Si1.99H3.89O10 on the basis of O = 10. It is transparent, blue in colour with vitreous lustre. The streak is white and the cleavage good in one direction. The hardness is 5–5.5. The calculated density is 3.3 g cm−3. It is colourless in thin section and optically biaxial positive with α = 1.664 (2), β = 1.674 (2), γ = 1.688 (2) and 2V(calc.) = 81°. It occurs in a thin veinlet cutting a lavender-coloured Ti-bearing jadeitite. The veinlet includes irregularly-shaped aggregates composed of minute tabular crystals of itoigawaite up to 50 µm across and minute jadeite crystals with interstitial natrolite aggregates. Itoigawaite is considered to be crystallized from fluid during later stage activity of high-P/T metamorphism. The name is for the locality.

Bariosincosite is a new barium vanadium phosphate hydrate from the Spring Creek Mine, near Wilmington, South Australia. The new mineral occurs as irregular clusters of pale green, very thin platey crystals up to 250 µm across and 2 to 5 µm thick. The tetragonal crystals are tabular on {001} and the other form present is {100}. Associated with bariosincosite are quartz, cuprite, native copper, fluorapatite, whitlockite, baryte and springcreekite, BaV33+ (PO4)2(OH,H2O)6. Bariosincosite appears to have formed under supergene or low-temperature late-stage hydrothermal conditions. Electron microprobe analysis yielded: BaO 23.20; SrO 4.19; CaO 0.36; VO2 31.55; Fe2O3 0.20; Al2O3 0.50; P2O5 28.15; H2O 13.93 (calculated). These data give an empirical formula of (Ba0.77Sr0.20Ca0.03)∑1.00[(V0.964+ Al0.03Fe0.013+)∑1.00O(PO4)]2·4H2O, calculated on the basis of two P atoms. The simplified formula is Ba(V4+OPO4)2·4H2O. The mineral is transparent with a very pale green streak, a vitreous lustre and an estimated Mohs hardness of 3. The strongest lines in the X-ray powder pattern are [dobs (Iobs) (hkl)] 6.414 (20) (110, 002); 5.748 (70) (111); 4.552 (30) (112, 200); 3.198 (20) (220, 004); 3.100 (100) (203, 221); 2.847 (40) (222, 114); 2.786 (80) (311); 2.368 (30) (313, 115); and 2.017 (100) (420, 332, 116). These data were indexed on a tetragonal cell, with a = 9.031(6), c = 12.755(8) Å and V = 1040(1) Å3; the space group is probably P4/n or P4/nmm. For Z = 4 and using the empirical formula, the calculated density is 3.306 gm/cm3. Bariosincosite is uniaxial negative with ω = 1.721(2) and ε = 1.715(2) (white light); pleochroism is weak from colourless (E) to pale green (O), absorption O > E. The mineral is named for the relationship to sincosite, Ca(V4+OPO4)2·4H2O.

A recent study of granitic gneisses in the ultrahigh-pressure (UHP) metamorphic terrane from Dabie Shan, central China reveals that allanite-(Ce) is a widespread REE-bearing accessory phase. The microprobe analyses show that allanites-(Ce) have nearly uniform chemical compositions, with total REE contents ranging from 23 to 28 wt.% and a La/Ce ratio of 0.57–0.73. All allanites-(Ce) are replaced or rimmed by epidotes and commonly form a relatively REE-poor rim near the interfaces. The textural relations and mineral chemistry suggest that allanite-(Ce) crystallized prior to metamorphism and therefore was of igneous origin, whereas the surrounding epidote was the product of metamorphism. Granitic gneiss, composed chiefly of sodic plagioclase, microcline and quartz with minor amounts of Mn-rich garnet, biotite, low Si phengitic mica, epidote, chlorite and sometimes amphibole, was formed at 495°C and ∼5 kbar, corresponding to the retrograde metamorphism of UHP rocks. Accordingly, it is believed that granitic gneisses have not experienced UHP metamorphism. This implies that a large scale tectonic juxtaposition developed before the epidote-amphibolite facies retrograde metamorphism of UHP rocks during the late continental collision in Dabie Shan.

Pegmatite cutting chlorite schist in the Minas fault at McKay Head, Nova Scotia, consists of Cl-rich (2.7–3.8 wt.% Cl) marialitic scapolite (EqAn21–32) with interstitial, apparently primary analcite, hematite and rutile, and later (including vug-lining) analcite, pyrite, chlorite, titanite and calcite, and cross-cutting epidote veins. Some of the latter phases might have crystallized from residual pegmatitic fluids. Unlike many other primary scapolite-bearing igneous rocks, the McKay Head occurrence has compositional affinities with mafic (rather than felsic) systems: it is enriched in transition metals (e.g. Cr≤53 ppm), and has very low LILE concentrations (e.g. Rb<10 ppm; U<1 ppm; Th<2 ppm; Ba<20 ppm) and Rb/Sr ratios (~0.05). The presence of interstitial rutile and hematite rather than ilmenite indicates that the pegmatitic fluid was oxygenated late (T~400°C) in its crystallization history.

The pegmatite is interpreted to be related to highly sodic hydrothermal solutions derived from (or affected by) early Carboniferous evaporites of the Windsor or Horton groups. Compositionally-similar fluids, perhaps also related to an evaporite source, may be responsible for a regional, early Carboniferous Na-metasomatic event that altered a suite of alkaline granitoid intrusions shortly after their emplacement.

Chloritoid with significant Mg-Fe zoning occurs as lath-shaped porphyroblasts and as clusters of subradiating crystals in the Triassic Verrucano metapsammite (quartz + muscovite + chlorite + chloritoid ± kyanite) of the Massa Unit, Alpi Apuane. Two main types of chloritoid zoning profiles were found. The first type is characterised by gradual increase in Mg from core to rim of the porphyroblasts. In the second type the Mg content is constant from the core to the inner rim, but sharply decreases in the outer rim. Both types of zoning have been interpreted as the result of prograde growth during the Alpine metamorphism. The temperature, estimated using the chlorite-chloritoid thermometer, ranges from 467 to 560°C.

Goldmanite, the vanadium analogue of grossular and andradite, was found as subrounded green porphyroblasts ranging from 0.1 to 1.7 mm in size in the carbonaceous black slates from the Deokpyeong area of the Ogcheon belt in Korea. A radiating aggregate of slightly curved blades of goldmanite crystals displays birefringence and replaces the fine-grained black matrix. The V2O3 content ranges from 21.9 to 26.6 wt.% (24.0 wt.% average), higher than previously reported values. The calculated mole % of the goldmanite end-member ranges from 72 to 91. Its cell dimension was calculated to be 12.04 Å from X-ray diffraction. The black slate in the Deokpyeong area is the richest known accessible source of relatively pure goldmanite.