The new mineral bakakinite, ideally Ca2V2O7, was found in the high-temperature (not lower than 500°C) exhalations of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with anhydrite, svabite, pliniusite, schäferite, berzeliite, diopside, hematite, powellite, baryte, fluorapatite, calciojohillerite, ludwigite, magnesioferrite, anorthite, titanite and esseneite. Bakakinite forms flattened crystals up to 30 × 5 μm, typically distorted. The mineral is transparent, colourless or pale yellow, with strong vitreous lustre. Electron microprobe analysis gave (wt.%): CaO 37.04, SrO 0.26, SiO2 0.16, P2O5 1.48, V2O5 49.47, As2O5 10.85, SO3 0.35, total 99.61. The empirical formula calculated on the basis of 7 O apfu is (Ca1.99Sr0.01)Σ2.00(V1.64As0.28P0.06Si0.01S0.01)Σ2.00O7. The Dcalc is 3.463 g cm–3. Bakakinite is triclinic, P$\bar{1}$, unit-cell parameters are: a = 6.64(2), b = 6.92(2), c = 7.01(2) Å, α = 86.59(7), β = 63.77(7), γ = 83.47(6)°, V = 287.0(5) Å3 and Z = 2. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 4.647(27)(111, 0$\bar{1}$1), 3.138(76)(002), 3.103(100)(120, 121), 3.027(20)(021), 2.960(81)(200), 2.158(19)(031, 302), 1.791(16)(320), 1.682(16)(114) and 1.584(17)(1$\bar{3}$3, 403). Bakakinite is a natural analogue of synthetic Ca2V2O7. The mineral is named in honour of the outstanding Russian crystallographer and crystal chemist Vladimir Vasilievich Bakakin (born 1933).

The structure called cone-in-cone attracted my attention when I was working at certain forms of jointing and spherulitic structures in rocks, and has been studied in a desultoiy fashion ever since. Moreover, the Museum of University College possesses some good specimens of cone in-cone obtained by the late Prof. Morris, and I received a present of others, which had been used by Mr. W. S. Gresley for his suggestive paper when he left England for America. But though I formed some general conclusions on the subject, I abstained from writing, because I felt doubt concerning one point of importance, and had never seen a good example of cone-in-cone in the field.

Deposits of Diatoms have been long known to exist in Scotland, but such deposits have so far always been of limited extent. Specimens for the microscope have been readily obtained from certain localities, such as Peterhead, but the occurrence of large deposits covering great tracts of land was unknown.

In the year 1881 my attention was directed, by Mr. Hamilton Bell, to a white substance he had obtained from the Peat of Aberdeenshire. During April, 1882, I read a short paper before the Edinburgh Geological Society in which I gave the analysis of a sample received from Mr. Bell, with particulars furnished by the Rev. Geo. Davidson, Minister of Logie Coldstone, Dinner, who also kindly furnished a list of the Diatomaceæ he had identified in the deposit. The list contains some 200 species.

The name xanthoconite was given by Breithaupt (1) to a mineral which he found in 1840 associated with proustite upon an old ore-specimen in the collection of the Berg-Akademie at Freiberg. He describes it as occurring in reniform masses with a surface consisting of microscopic crystals, but with a crystalline granular interior.

During the year 1919 specimens of some of the meteorites preserved in the Public Museum of King Willlam's Town, South Africa, were kindly placed by the Curator, the late Yr. F. A. O. Pyre, at the disposal of the writer for investigation. One of these specimens was a meteoric iron labelled Mount Ayliff, another a mass of oxidized material labelled Western Cape Province, and a third a small piece of iron labelled ‘found on Elandsburg at an altitude of 6,000 ft. in 1888’ Unfortunately Mr. Pyre was not in a position to supply very much more information about the specimens.

Geological disposal (GD) of radioactive waste is close to becoming a reality for Finland, Sweden and France. High-technology development and advanced knowledge has made it possible to defend the feasibility and the safety of such facilities, making the European Union a leader in the field. Other European countries are closely behind, developing high competence through advanced research programmes, research infrastructures and public engagement.

At the other extreme, there are countries whose GD programmes are at an early stage and no systematic research programmes exist. These include several new Member States but not the Czech Republic and Hungary, both of which have already initiated a siting process.

There are several common reasons for this delay in schedule: small and relatively younger nuclear energy programmes, return of the spent fuel (especially from research reactors) to the countries of origin, open fuel cycle concept (requiring at least 50 years of wet and dry storage). In this context, there has been little pressure on setting up an early GD programme. Currently their disposal concepts are only generic and in most of these countries need updating, taking into account the current socio-economic context.

However, some of these new Member States still aim to have a GD in operation within several decades, e.g. 2055 in Romania and 2067 in Slovenia. Strategic planning based on the experience of more advanced programmes shows the GD process should start immediately in order to be able to achieve these deadlines.

In this context, the implementation of the EC Directive 70/2011 gives the opportunity to progress the advancement of the GD process in these countries.

The high-temperature behaviour of a feldspar-group mineral, filatovite (with the simplified formula: K(Al,Zn)2(As,Si)2O8), in which the Al:As:Si ratio is close to 2:1:1), was studied by in situ high-temperature single-crystal X-ray diffraction and in situ high-temperature (hot stage) Raman spectroscopy up to 600°C. In the temperature range studied (25–600°С) filatovite does not undergo any phase transition, whereas at 800°C it decomposes to X-ray amorphous phase(s). The evolution of 12 main Raman bands was traced during heating, which indicates a gradual change in the crystal structure. The thermal expansion coefficients of filatovite demonstrate a sharply anisotropic character of thermal expansion: the maximal expansion is close to the a axis (α11 = 17.7(1) × 10–6 °C–1), whereas along the b and c axes the thermal expansion coefficients are close to zero. Such behaviour is typical for minerals with a similar crystal structure topology; it indicates the dominant role of structure geometry in the thermal behaviour of the mineral.

Calcite is widespread in amygdales associated with the zeolites; the characteristic forms being and a steep scalenohedron in the zone , usually . Crystals from one locality have faces of , a form new to calcite.

Conclusions concerning the unit-cell contents and chemical formula of a mineral are all too often drawn from a small part of the available data. A procedure is outlined by which any chemical analysis for which a density is available can be utilized, provided X-ray data are available for a reasonable range of analysed specimens. The effects of possible errors in the determination of water, and in the assessment of essential and non-exsential water, are discussed both qualitatively and quantitatively.

A survey of all available data for anthophyllite has not disclosed any specimens in which the number of oxygen atoms per unit cell is significantly in excess of 96 with the possible exception of the Glen Urquhart gedrite and the Edwards (New York) material. But it is certain that the number of cations per unit cell is normally well in excess of 60 (partial occupation of the A lattice positions), and that, although ‘excess’ water in sonic fibrous anthophyllites may be adsorbed impurity, the number of hydroxyl groups in others is well in excess of 8 per unit cell; it is also fairly clear that the number of hydroxyl groups may fall below 8 per unit cell.

The response of garnet and zircon to prograde amphibolite-facies metamorphism in late Proterozoic mica schists from the Scottish Highlands has been investigated. Spatial analysis of zircon populations using scanning electron microscopy was undertaken in Dalradian Schists that have undergone a sequence of prograde garnet growth and localised breakdown reactions involving coupled dissolution–reprecipitation. Fluid availability and matrix permeability strongly control this metamorphic response and different generations of garnet contain radically different populations of metamorphic micro-zircon and associated changes in the detrital zircon population. Micro-zircon abundance increases during garnet growth, whereas that of detrital zircon decreases. The mineralogy of the matrix influences zircon abundance in porphyroblast phases, where garnet overgrows a micaceous matrix zircon-rich garnet forms and where it overgrows a quartzofeldspathic matrix the result is zircon-poor garnet. Following garnet growth, micro-zircon abundance decreases at each stage of the prograde reaction history, with sillimanite-zone schists containing the lowest abundance, suggesting micro-zircons are texturally less stable at staurolite- and sillimanite-grade metamorphism. Micro-zircons are distributed evenly across host minerals in the matrix, with the exception of retrograde chlorite where micro-zircons are absent due to fluids removing Zr before new zircon can precipitate. There is an overall decrease in the mode of zircon at each stage of the reaction history, indicating that zircon is a highly reactive phase during amphibolite-facies metamorphism and is very sensitive to individual prograde and retrograde reactions.

Warwickite constitutes about 5% of an outcrop of metamorphosed ultramafic rocks of Precambrian age in North-West Greenland. It occurs as slender grains, several millimetres long, and in anhedral grains up to 5 mm in size, together with forsterite, pleonaste, phlogopite, magnetite ± tourmaline. Post-metamorphic alteration of warwickite produced a network of boron-rich minerals and magnetite. The warwickite, containing up to 9.72% Al2O3, displays a significantly different chemical composition from warwickite elsewhere, such as that in recrystallized limestones from the type locality Warwick, New York, and in lamproitic and carbonatite-like rocks at Jumilla, Spain.

Chemical analyses, optical properties, and specific gravities are presented for nine axinites. A reciprocal substitution relationship is demonstrated between Mg and Mn2+, and a linear variation diagram is constructed between refractive indices and the (Fe2++Fe3++Mn2++Ti) ions calculated on the basis of 16(O,OH). The composition of these axinites is independent of the composition of their host rocks; their colour appears to be independent of the Fe2+/Mn2+ ratio for the range of iron and manganese values of the specimens investigated.

Two new finds of stony meteorites north-west of Kalgoorlie are described, and the masses covered by brief petrographic descriptions.

There is general agreement as to the basis on which most major igneous rock-types are defined despite some difference of opinion as to quantitative limits. This is not true of diorites and gabbros (or of their hypabyssal and volcanic equivalents) in distinguishing between which at least four different criteria are in current use.