Late Tertiary-Quaternary volcanism around Calatrava, within the Hercynian massif of central Spain, is alkaline mafic-ultramafic, with ∼250 centres, mainly monogenetic cones and vents, with melilitite the most abundant eruptive. Carbonatite may be expected in association with melilitite and a clear example of magmatic carbonate emerged from a brief field reconnaissance. It is a vent filled with a mixed eruption of glassy melilitite lapilli in a carbonate matrix. Levels and profiles of trace elements are inseparable from recognized carbonatite, and totally unlike those in local sedimentary limestone and caliche. C and O isotopes are the same as those reported for carbonatite ashes in other provinces. Carbonate is present as globules in the melilitite glass, and as inclusions within large clinopyroxene and olivine grains, which are largely xenocrystic. Euhedral spinels in melilitite and carbonate matrix are chromite mantled with titano-magnetite, reported previously only from high-temperature kimberlite. Wehrlite fragments indicate direct eruption from the mantle. Phlogopite and chromian spinel are found only as inclusions in the olivine, pointing to a phlogopite-carbonate mantle source region of the type favoured for carbonatite and melilitite melt generation. Calatrava represents the most southerly and westerly expression in mainland Europe of intra-continental carbonatite-melilitite volcanism. Follow-up field visits have shown that carbonate volcanism is extensive and voluminous throughout the province, requiring a long-term research programme.

We have analysed a rare occurrence of orange-brown manganotantalite lamellae (visible in hand specimen), intergrown with microlite [(Ca,Na)2(Ta,Nb)2(O,OH,F)7], aggregates of ferrotapiolite, bismuth minerals and apatite to understand more about the mechanisms of crystal growth and secondary modification in Ta-rich minerals. The intergrowth occurs within amblygonite/montebrasite nodules near the quartz core of the highly fractionated rare-metal Li/Be/Ta pegmatite at Rubicon, Karibib, Namibia. Electron microprobe analyses show that manganotantalite lamellae are variable in composition. Primary microlite (Ta2O5 82%, 1.97 Ta a.p.f.u.) forms the matrix mineral between the lamellae. Textural relations suggest an exsolution origin for the lamellae. Manganotantalite is represented by three generations: (1) primary late magmatic; (2) disequilibrium exsolution lamellae; and (3) subsolidus replacement. Crystallization commenced with primary microlite and likely simultaneous intergrowth between ferrotapiolite and a first generation of late-magmatic primary manganotantalite with low Ta (1.1—1.5 a.p.f.u.). On cooling this was followed by exsolution of manganotantalite lamellae, generation (2) with low—medium Ta (1.27—1.7 a.p.f.u.). The replacement of microlite by a highly fractionated late-stage melt rich in Mn2+, Ca2+ with low Na+ finally produces a third generation (3) of manganotantalite with high Ta (1.72—1.99 a.p.f.u.) at the contact with microlite. Native bismuth and bismutite cut across microlite and pseudomorph lamellae as a final hydrothermal replacement. Apatite is ubiquitous at the contact with amblygonite. The stability field of microlite may be extended by incorporation of CaTa2O6-rynersonite and Ca2Ta2O7 — idealized, components in solid solution. However, rynersonite-CaTa2O6 with distorted octahedra has some structural templates which are similar to the structure of pyrochlore (microlite). Hence, via the perovskite/pyrochlore analogy, hypothetical exsolution of manganotantalite-type structures may occur from a microlite (pyrochlore) host by solid-state diffusion via metastable rynersonite-type intermediates. Such a mechanism has the potential to explain the crystallographically controlled intergrowth textures and the compositional heterogeneity.

We report a new type of högbomite in a spinel- and sapphirine-bearing silica-deficient Mg-Al rock from Manavadi at the northern margin of the Madurai Block along the Palghat-Cauvery shear zone system, which defines the Archaean-Proterozoic collisional boundary in southern India. Högbomite occurs here as fine- to medium-grained euhedral to subhedral crystals enclosed within or along grain boundaries of greenish spinel. It is compositionally very unique due to the lack of TiO2 (<0.2 wt.%) and enrichment in Al2O3 (66.4—70.8 wt.%) compared to other occurrences. The variety of högbomite described in this study, confirmed by laser Raman spectroscopy, has not been reported elsewhere previously. Högbomite in this study is subdivided into three groups based on the XMg (=Mg/ (FeTotal+Mg)) ratio; 0.54—0.57, 0.61—0.73 and 0.77—0.79. Compositional data suggest a linear element substitution of 3(Fe+Mg) = 2Al for the Ti-free högbomite, a trend that is distinct from previously reported Ti-bearing högbomites. Textures and mineral chemistry data suggest that the following reaction took place at retrograde stage (T <800°C): spinel + H2O + O2 → högbomite + corundum + magnetite, implying that introduction of hydrous and oxidized fluid as well as low bulk-Ti content played an important role in the formation of Ti-free högbomite.

Calc-alkaline dacites from the Setouchi volcanic belt contain garnet crystals that are classified petrographically and chemically into two types: type I and type M. Type-M garnets are characterized by acicular sillimanite inclusions or dissolution textures, and may be accompanied by xenolith fragments. They exhibit extensive compositional zoning with an increase in MgO/FeO and decrease in MnO content towards the margin. These petrographical and compositional features are identical to those of garnets from metamorphic xenoliths entrained in the Setouchi volcanic rocks, suggesting a xenocrystic origin for the type-M garnets. In contrast, type-I garnets lack sillimanite inclusions and have different rim compositions from the type-M garnets. Transmission electron microscope analysis has revealed the presence of minute glass inclusions in the type-I garnets, which indicate conclusively that these garnets grew in the presence of a melt. Type-I garnets have oscillatory zoning characterized by an antipathetic variation between FeO and MgO. This zoning was probably caused by magma heterogeneity within magma batch. Differences in rim compositions between the two types of garnets, and the presence of reaction rims indicate that the xenocrystic type-M garnets were incorporated into the magma after phenocrystic type-I garnet became unstable due to decompression during magma ascent.

Redgillite, Cu6(OH)10(SO4)·H2O, space group P21/c, a 3.155(3) Å, b 10.441(8) Å, c 19.436(16) Å, β 90.089(13)°, V = 640.2(9) Å3, Z = 2, is a new mineral from Silver Gill, Caldbeck Fells, Cumbria, England. The strongest six lines of the X-ray powder-diffraction pattern [d in Å, (I)(hkl)] are: 9.72 (90) (002), 7.11 (100) (012), 4.60 (30) (022), 4.068 (20) (023), 2.880 (30) (112,11), 2.318 (50) (131,13). It occurs as translucent to transparent grass-green bladed crystals up to 0.15 mm long with squared-off or tapering terminations; usually in radiating groups. Forms observed are {001} prominent, {010} as composite stepped faces, and {100} irregular. Redgillite has white streak, vitreous lustre and Mohs hardness of ∼2. Blades are slightly flexible with irregular fracture and exhibit a perfect {001} cleavage and good {100} and {010} cleavages. The measured density (by sink-float) is 3.45(5) g/cm3; the calculated density is 3.450 g/cm3. The mineral dissolves slowly in dilute HCl. Redgillite is biaxial- negative with α = 1.693(2), β = 1.721(2), γ = 1.723(2), 2V = 30(2)° (meas.) and 30° (calc.); dispersion is r > v, medium; pleochroism: Y blue-green α X blue-green α Z yellow-green; orientation: X ≈ c , Y = b, Z ≈ a. Electron microprobe analyses yielded CuO 68.9, SO3 11.6, total 80.5. With water inferred from the structure analysis, the empirical formula is: Cu5.995(OH)9.991(SO4)1.003·H2O. Redgillite is typically found in thin fractures in partly oxidized sulphides where it is commonly associated with langite and more rarely with malachite, cuprite, connellite and brochantite. The name is for the Red Gill mine, from which the mineral is best known. The crystal structure of redgillite was determined and refined to R = 0.090 for 1529 observed reflections [I > 2σ(I)]. The redgillite structure consists of Jahn-Teller distorted CuO6 octahedra and SO4 tetrahedra. The octahedra share edges to form sheets that are zig-zag in cross section. The SO4 tetrahedra share an oxygen with the Cu layer and link the layers by hydrogen bonds to OH groups. The crystal structures of wroewolfeite, langite, posnjakite, spangolite and schulenbergite are similar to redgillite. They all contain edge sharing CuO6 layers connected to SO4 groups with the layers bridged via hydrogen bonds.

Coarse-grained mertieite-II [Pd8(Sb,As)3] crystals (up to 2.5 mm across) with inclusions of sperrylite and intergrown with keithconnite [Pd3(Te,Bi)], cooperite-braggite, a Pt-Pd-Hg alloy, a (Pd,Pt)9Te phase and Au-Ag alloy occur in alluvial sediments in the Darya river, Aldan Shield, Russia. The primary PGM assemblage underwent alteration with formation of a very fine-grained mixture of Pd-bearing oxides and hydrated oxides. The Pd oxide/hydrated oxide aggregates (up to 100 μm wide and ~1 mm long) occur along crystallographic planes, on grain boundaries and fractures, occasionally intergrown with goethite. The Pd-O-bearing compounds formed after (1) mertieite-II (Sb content reaches 23 wt.%), (2) keithconnite (variably enriched in Te, up to 7 wt.% and Bi, up to 6 wt.%) and (3) potarite (with high Hg content, up to 35 wt.%). The variably oxidized and hydrated PGM assemblage can be attributed to supergene alteration and small-scale element redistribution under cool climatic conditions with a limited degree of leaching.

We report preliminary petrographic and mineral chemical data for a rock hosting an unusual mineral assemblage from Långban, Värmland, Sweden. The rock is a two feldspar-scapolite-spessartine-romeite skarn. The bulk composition and high degree of enrichment in Pb, Sb and As suggest that the rock was formed by reaction between a pre-existing Mn skarn containing the chalcophiles and a potassic granite, with loss of silica, alkalis and CO2. The alkali feldspar is a Pb-rich hyalophane, averaging Or63Ab19Cs15Pb03, the plagioclase feldspar a Pb-rich labradorite, An48Ab48Or02Pb02, and the scapolite a 'mizzonite' (Ca/(Na+Ca) = 0.66—0.70). These minerals show their highest Pb contents recorded in nature to date: up to a maximum of 5.7 wt.% PbO in the hyalophane, 2.1% PbO in the plagioclase, and 5.3% PbO in the scapolite. Laser ablation ICP-MS of a scapolite grain detected substantial Be up to 1.7 wt.% BeO (0.6 Be per 12 tetrahedral cations), as well as Pb up to 7.05 wt.% PbO. The Be is incorporated into scapolite via the coupled exchange [Be(OH)][Al(CO3,SO4)]—1. This is the first documentation of scapolite as the major repository for Be in a rock.

The romeite also contains substantial Pb, and shows extensive solid solution towards end-members containing Fe3+, Ti and Sb3+. In some analyses, the dominant end-members are and its Pb analogue rather than (Ca,Pb)2Sb2O7. Complex exsolution textures are displayed in the hyalophane, by hancockite-epidote, romeite-bindheimite and hedyphane-johnbaumite. Ca-rich scapolite and hancockite appear to be new minerals for the Långban deposit.

The mineralogy appears consistent with the regional peak conditions of P = 3 kbar, T > 600°C. Several potential thermobarometers for Mn-rich skarns are identified in this rock.

SHRIMP U-Pb zircon and titanite dating have been used to constrain the timing of mid- to lower- crustal metamorphism (∼650—700°C and 8—11 kbar) and syn-kinematic melting in the granitoid gneiss- dominated terrane south of the Barberton greenstone belt, South Africa. This study is concentrated on a clastic metasedimentary unit exposed in one of several greenstone remnants and a late-kinematic trondhjemite intrusive into spatially associated mixed gneisses. Locally, the clastic metasediments show extensive replacement of garnet and plagioclase by epidote and titanite. The titanites yield an upper intercept date of 3229±9 Ma, and provide a minimum age for the peak of metamorphism. Zircons separated from the same unit record a range of concordant and near-concordant 207Pb/206Pb dates between ∼3560 and 3230 Ma, the youngest group yielding a weighted mean date of 3227±7 Ma. This range of dates is interpreted to be due to a combination of metamorphic recrystallization and high- temperature Pb-loss in originally detrital zircons during regional metamorphism. A minimum age for the timing of deformation is given by the emplacement age of 3229±5 Ma for the late-kinematic trondhjemite. Thus, geochronological data support the notion of a major metamorphic episode that coincided with the proposed short-lived terrane accretion event in the centre of the Barberton greenstone belt.

The first Italian occurrence of cumengéite, a rare Pb and Cu hydroxychloride, is described from Vesuvius (Italy). Italian cumengéite has a volcanic origin (it occurs in the fumarole), which is unique for that mineral. The mineralogy of Vesuvius' fumarole is outlined briefly. A powder X-ray diffraction (XRD) pattern of cumengéite is presented. The crystal structure of cumengéite has been refined (R = 0.036) using single-crystal XRD data. Cumengéite is tetragonal, space group I4/mmm, a 15.1007(2), c 24.4940(4) Å. In the structure of cumengéite there are five independent Pb atoms, which are linked to 6—9 anions in five different ways. The structural study revealed the presence of two independent and previously unobserved water molecules, and led to the revision of the accepted chemical formula for the mineral: the new formula is Cu20Pb21Cl42(OH)40·6H2O. Analytical data taken from the literature for cumengéite from Boléo, Mexico (the type locality), as well as a new structural study carried out on the type material confirmed the new formula.

Aspidolite, the Na analogue of phlogopite, ideally NaMg3AlSi3O10(OH)2, occurring in hornfels from a contact aureole in Kasuga-mura, central Japan, has been approved as a mica species by the Commission on New Minerals and Mineral Names of the International Mineralogical Association. Aspidolite is interleaved with and surrounded by phlogopite. Based on its mode of occurrence, phlogopite is classified into two types; (1) phlogopite interleaved with aspidolite (= interleaved phlogopite) and (2) phlogopite rim. The aspidolite-phlogopite assemblage is associated with amphibole (pargasite-magnesiosadanagaite), titanite, calcite, scapolite, apatite, pyrrhotite and chalcopyrite. A representative chemical formula of aspidolite is (Na0.90K0.10)∑1.00(Mg2.27Al0.41Fe0.232+Ti0.05)∑2.96 (Al1.44Si2.56)∑4.00O10(OH1.97F0.03)∑2.00. Aspidolite has almost fully occupied the interlayer site; its Na/(Na+K) ratio ranges from 0.67 to 0.95. It has more tetrahedral Al (1.38—1.48 a.p.f.u. for O = 11) than the ideal aspidolite end-member showing progression of tschermakite-type substitution. The alternation of aspidolite and phlogopite parallel to the (001) plane may indicate a miscibility gap between these two phases. The phlogopite rim is interpreted as a later product, probably formed metasomatically. Aspidolite is optically biaxial negative with elongation positive and Z ‖ cleavage. Two polytypes (1M and 1A) of aspidolite were identified in X-ray powder diffraction patterns. Aspidolite-1M is monoclinic, space group C2/m, with refined unit-cell parameters a = 5.291(8), b = 9.16(2), c = 10.12(2) Å, β = 105.1(1)°, V = 473(1) Å3, Z = 2. Aspidolite-1A is triclinic, space group C, with a = 5.289(6), b = 9.16(1), c = 9.892(9) Å, α = 94.45(9), β = 97.74(9), γ = 90.0(1)°, V = 473.4(9) Å3, Z = 2.

Four distinct textures and related compositions of kosmochlor (Ko) and chromian jadeite in rocks from the Myanmar jadeitite area are described: (1) spheroidal or ellipsoidal aggregates with a corona texture surrounding relict chromite; (2) spheroidal or ellipsoidal aggregates with a core of jadeite; (3) granoblastic textures in undeformed coarse-grained clinopyroxene rocks; and (4) recrystallized fine-grained aggregates in deformed jadeitite. Nearly pure kosmochlor (97 mol.% NaCrSi2O6) was found in type 2 textures, closest to the end-member reported so far from a terrestrial rock. Sharp compositional boundaries between kosmochlor and chromian jadeite of variable composition are interpreted to be related to progressive crystallization or replacement at differing conditions. The compositions analysed plot along the kosmochlor-jadeite join. In contrast to conclusions of previous studies on the Myanmar clinopyroxenes there is no unequivocal evidence for miscibility gaps. The preservation of relict chromite in the centre of coronitic spheroidal or ellipsoidal aggregates of kosmochlor and jadeite indicates a metasomatic origin from a peridotite protolith at an inferred minimum pressure of 1.0 GPa and temperatures of 250—370°C. Recrystallization during later ductile deformation of the clinopyroxene rocks in the dislocation creep regime leads to fine-grained aggregates of chromian jadeite, which are of particular gemmological interest.