This instrument is a microscope stage-micrometer for the quantitative estimation of one to six different kinds of constituents in a substance, by the Delesse-Rosiwal method. It is intended, primarily, for linear micrometrie analysis in petrography, but has similar uses in mineralogy, chemistry, and metallography. Economic applications include the volumetric evaluation of components in building stones, road-metals, sSlid fuels, refractories, and slags.

The object of this new design is to combine speed and accuracy in operation with a particularly compact construction, mechanical simplicity, and strength. Special consideration has been given to the wear and cleansing of bearings, the definition of scale-divisions and zero-marks, and the rigidity of all supports for moving parts.

While studying some of the early works on minerals I came across an obvious difficulty: several minerals, amongst which lapis-lazuli is the most startling, are described in Latin as flavus, yellow or flaxen-coloured, not blue. This error has been copied into a book in English. The solution is less obvious than the difficulty, and it may therefore be worth while to put it on record for other workers on similar lines.

Optical microscopy of doubly polished thin sections of North Pennine sphalerite has revealed a range of previously unrecognised textures for the Alston Block mineralisation. Delicate growth zoning, interrupted by numerous solution disconformities, was seen in transmitted light. Two principal varieties of growth-banded sphalerite are recognised; the earlier (Type 1) is characterised by the development of thin opaque bands. Type 2 has colour bands between yellow and brown, correlated with iron content. In Type 1, iron levels (up to 3 wt.%) are not sufficient to account for the observed opacity. Ultra-violet and infra-red techniques failed to detect any organic inclusions. Electron microscopy revealed locally high concentrations of sub-micrometre inclusions, both beam-stable and beam-unstable, and a variety of growth-related crystal defects.

Fluid inclusion thermometry in both sphalerite varieties and the accompanying quartz gangue implies a saline mineralising fluid (20–25 wt.% equiv. NaCl) at a relatively low temperature (100° to 140°C). Tubular inclusions are conspicuous. A deformation-induced lamelliform optical anisotropy is superimposed on a growth-related grid-iron anisotropy. Growth band offset is apparent where the deformation fabric cross-cuts the growth banding. Deformation on {111} twin and slip planes was indicated by electron microscopy.

The important influence that the radioactive decay of the radio-elements uranium and thorium has had on the geochemical distribution of lead is now well appreciated, but little is known about the possible geochemical implications of the radioactivity of rubidium.

Like its alkali metal homologue potassium, rubidium is β radioactive and slowly disintegrates into a stable isotope of strontium: small quantities of strontium have therefore been accumulating in various minerals since the earth's crust first consolidated. This paper will describe firstly, the abundance of radiogenic strontium in the earth's crust as a whole, and secondly, the distribution of radiogenic strontium in various minerals and rocks, in particular those which are of igneous origin.

In view of the important uses to which the metal titanium has been applied in recent years, it seems fitting that some tribute should be paid to its Cornish discoverer, the Rev. William Gregor, and with this end in view I have collected the following facts concerning this now almost forgotten distinguished early chemist.

The Rev. William Gregor, M.A., chemist and mineralogist, was the younger son of Francis Gregor, member of an old Cornish family of Trewarthenic, Cornelly, CornwalI. Born on December 25, 1761, he was educated at Bristol Grammar School, and it was while there that he first developed a taste for chemistry.

In two-circle goniometry as usually practised, the zone-adjustment is almost invariably used. It would be difficult to discover the reasons which have led to this unfortunate neglect of the face-adjustment; actually the face-adjustment has all the advantages of the zone-adjustment without its defects.

Chemical analyses and optical properties of ten orthopyroxenes, two clinopyroxenes, and six biotites (partial analyses) are presented from basic to intermediate charnockites of the Garbham area. The orthopyroxene is hypersthene to ferrohypersthene and the clinopyroxene is sahlite. Biotite has secondarily formed from pyroxene, particularly orthopyroxene, as a result of injection of potassic fluid in the basic charnockite. By combining the data of Srikakulam with those from other areas of the world it is shown that during the transformation of pyroxene to biotite in charnockitic rocks, in general, Mg and Fe 2+ attain near-equilibrium distribution between orthopyroxene and biotite as well as between clinopyroxene and biotite. The magnesium distribution coefficient (KD) of coexisting orthopyroxene and biotite is found to increase with the increase of temperature of biotite formation. A tentative geothermometric scale has been proposed plotting temperature of biotite formation against magnesium distribution coefficient of coexisting orthopyroxene and biotite. According to this scale, biotite in basic and semibasic charnockites from Garbham has formed between 285 and 465 °C.

Black tourmalines from seven granitic pegmatites (Golodnaya, Kazennitsa, Mokrusha, Kopi Mora, Zheltyye Yamy, Buzheninov Bor and Ministerskaya) related to the Murzinka pluton, Central Urals, Russia have been investigated using electron microprobe analysis, LA-ICP-MS, Raman and Mössbauer spectroscopy. Pegmatites are hosted by serpentinites and gneisses and are classified as schorl, oxy-schorl, fluor-schorl, dravite, oxy-dravite, foitite, oxy-foitite and darrellhenryite. The possible compositional evolution of tourmalines from the Ural pegmatites is as follows: Mg-rich dravite through to Fe-rich schorl, foitite and oxy-foitite to Fe- and Mn-rich darrellhenryite. The major substitutions in the tourmalines are: (1) Fe2+ ↔ Mg; (2) Al + WO2– ↔ Fe2+ + WOH–; (3) X-site vacancy + Al ↔ Na + Fe2+; (4) Al + WO2– ↔ Mg + WOH–; (5) X-site vacancy + Al ↔ Na + Mg; and (6) Fe ↔ Mn. Statical processing of the trace- and major-element composition distinguished three tourmaline groups: (1) trace Co, Ni, Pb, and major Ca and Mg; (2) uni-, di- and trivalent traces (Li, Zn, Ga) and di- and trivalent majors (Al, Mn); (3) U, Th, Hf, Ta, Nb, Y, In, and Sn which correspond to tri-, tetra-, and pentavalent high-field-strength elements. Mössbauer data shows the Fe3+/Fe2+ ratios in tourmalines from pegmatites hosted by gneisses (0.05–0.18) and serpentinites (0.28–0.65), indicates different oxidising environments. Raman data are consistent with the composition of the tourmalines.

The phonolites which are found in the volcanic region of Dunedin, New Zealand, are of a varied character. Some of them are of ordinary types, but others are nephelinitoid, and some of them have sodalite in abundance. Besides the phonolites, there are trachydolerites, some of which also contain sodalite as well as nepheline. There is also an abundance of tinguaites, in all of which nepheline is distinct and sometimes sodalite as well. All petrologists who have worked in this region are therefore perfectly familiar with the minerals sodalite and nepheline in many different associations and conditions.

An attempt is made to systematize the nomenclature of the calciferous and alkali amphiboles. The compositions of end-members can be plotted on a simple diagram, which can also be used to display the affinities of the naturally occurring minerals after deriving a basic atomic formula according to the rules given. The composition of an amphibole can in some cases be expressed quantitatively in terms of solid solution of two or three pure end-members.

A three-year European Commission project entitled performance assessment methodologies in application to guide the development of the safety case (PAMINA) was conducted in the period 2006–2009 and brought together 27 organizations from ten European countries, including the Nuclear Decommissioning Authority and Galson Sciences Ltd from the UK. The PAMINA project had the aim of improving and developing a common understanding of performance assessment (PA) methodologies for disposal concepts for spent fuel and other long-lived radioactive wastes in a range of geological environments.

Work undertaken within PAMINA focussed on four areas: (1) review of PA methodologies in participating organizations; (2) treatment of uncertainty in PA and the safety case; (3) other methodological advancements in PA; and (4) relevance of advanced PA approaches to practical cases.

The state of development of a radioactive waste disposal programme has a strong influence on the type of safety case and supporting PA that is produced. A range of PA methodologies has been developed by different waste management organizations. This paper presents a selection of conclusions from the PAMINA project, in the context of general understanding developed on what would constitute an acceptable safety case for a geological disposal facility, and outlines areas for further development.

The existence of an unidentified mineral in the riebeckite-microgranite of Mynydd Mawr has been known for almost exactly fifty years. It was first noticed by Harker and described by him in the following words: ‘The ground-mass [of the microgranite] is a finely granular admixture of quartz and orthoclase, as in an ordinary “microgranite”, but containing in addition another mineral which is often plentiful. It occurs in minute crystals of acicular or rectangular form, scattered through the ground-mass or included by the other constituents, and having usually a fluxional arrangement agreeing with that of the parallel hornblende and tourma]ine streams. The mineral is colourless, or in the larger crystals gives for vibrations parallel to the long axis a faint tint of indigo-blue. The crystals give high polarisation colours and straight, or nearly straight, extinction. They have a high refractive index, which causes them to stand out in relief when viewed by ordinary transmitted light.’

So far as I am aware no account of the microscopic structure of this rare and beautiful rock has yet been published. I have, therefore, thought that a brief description of its structure and some considerations concerning the origin of tourmaline rocks may be of interest to petrologists.

Boulders of the rock, as is well known, are abundant in the vicinity of the village of Luxullian (about five miles from the town of St. Austell, Cornwall), where I collected specimens in tho autumn of 1873; but I believe the rock itself has never been discovered in situ, though veins of different varieties of tourmaline rock are abundant in the granite of this and other districts in Cornwall, some of which occasionally rather resemble it, and the mineral frequently occurs in the granite itself, the felsite cleans, and the altered sedimentary rocks.

Petrofabric analysis of five specimens of laminated gabbro from the Centre 3 igneous complex, Ardnamurchan, was carried out by measuring orientations of grains of plagioclase, olivine, and augite with a Universal-stage. Linear alignments of primary precipitate mineral grains within the laminar fabrics were revealed by plots of data for coexisting plagioclase and olivine or augite. The plagioclase grains involved have tabular forms elongated parallel to their a-axes (rather than their c-axes). The olivine grains have flattened ovoid forms and the augite grains have sub-ophitic forms developed about prismatic primocrysts. In all specimens plagioclase displayed alignment of long grain-axes directed approximately down the dip of the lamination, save for one case in which a weak oblique alignment was observed. These lineations were reproduced by accompanying olivine and augite. The alignments are tentatively ascribed to flowage of a viscous boundary zone to the magma body in which crystal growth was taking place.