Munirite was found in the sandstones of Siwaliks formation of mid-Miocene to Pleistocene age. It occurs as small globular clusters of acicular crystals (2 to 3 mm long). Analysis gave V2O5 67.46, N2O 22.91, and H2O 10.26%. The X-ray powder diffraction pattern shows remarkable similarity to a synthetic compound NaVO3 · 1.9H2O (Lukacs and Strausievici, 1962).

Panskyite, Pd9Ag2Pb2S4, is a new mineral (IMA2020–039) discovered in the platinum-group element mineralisation of the Southern Kievey ore occurrence of the Fedorova–Pana layered intrusion, Kola Peninsula, Russia. It forms tiny anhedral grains (of 0.5 to 10 μm in size) in the interstices of rock-forming silicates, often forming tiny inclusions in base-metal sulfides (millerite, chalcopyrite, bornite and chalcocite) and complex intergrowths with other platinum group minerals (zvyagintsevite, laflammeite, vysotskite, thalhammerite, unnamed phase Pd9Ag2(Tl,Pb)2S4 and others). In plane-polarised light, panskyite is creamy white with weak bireflectance, weak pleochroism and distinct anisotropy with brown to grey rotation tints; it exhibits no internal reflections. Reflectance values for panskyite in air (R1, R2 in %) are: 43.8, 44.1 at 470 nm; 44.4, 44.7 at 546 nm; 45.6, 45.8 at 589 nm; and 47.2, 47.2 at 650 nm. Twelve electron-microprobe analyses of panskyite gave an average composition: Pd 55.61, Ag 12.36, Pb 23.50, Fe 0.21, Ni 0.24 and S 7.17 total 99.09 wt.%, corresponding to the formula (Pd9.05Fe0.07Ni0.07)Σ9.19Ag1.98Pb1.96S3.87 based on 17 atoms; the average of nine analyses on the synthetic analogue is: Pd 57.02, Ag 14.17, Pb 21.81 and S 7.44, total 100.44 wt.%, corresponding to Pd9.07Ag2.22Pb1.78S3.93. The density, calculated on the basis of the empirical formula, is 9.81 g/cm3. The mineral is tetragonal, space group I4/mmm, with a = 7.973(3), c = 9.139(3) Å, V = 581.0(4) Å3 and Z = 2. The crystal structure was solved from the single-crystal and powder X-ray diffraction data of synthetic Pd9Ag2Pb2S4. Panskyite is isostructural with thalhammerite (Pd9Ag2Bi2S4). The mineral name is for the locality, the Pansky massif of the Fedorova–Pana layered intrusion in the Kola Peninsula, Russia.

Many attempts have been made to discover the causes of the various colours displayed by minerals. If we except fluorescence and allied phenomena, the diiteren~ theories advanced may in general be grouped under one or other of the following classes:

1. (1) Colour may be due to an intrinsic property of atoms, ions, or molecules. Examples are copper atoms, chromate ions, and ferric oxide molecules.

2. (2) Colour is sometimes attributed to structural causes. The blue tints of certain halites have been explained in this way; but a fresh suggestion is made in this communication.

3. (3) A pigmentary impurity may cause the observed colour. The colour of the ruby is believed to be caused by the presence of a red chromic oxide. The blue tint of a Yorkshire aragonite is shown later to be due to a copper salt.

4. (4) Some minerals show plays of colours due to interference and/or grating effects. Labradorite and opal are cases in point. Into this group also fall minerals like bomite which become iridescent from tarnish.

Musgravite, Be(MgFeZn)2Al6O12, is associated with norbergite and minor chlorite in a Precambrian calcite marble within the gneissic basement in an internal part of the Caledonian mobile belt in Dove Bugt, North-East Greenland. It commonly occurs as vitreous black, idioblastic crystals (<7 mm in size) with combined rhombohedral and basal pinacoid forms. XRD data show that its space group is R3m and its unit cell dimensions are a 5.687 ± 0.002 Å and c 41.16 ± 0.02 Å. Electron microprobe and ICP-MS analyses have yielded BeO 5.51 wt.% and ranges in abundance (wt.%): Al2O3 68.74-70.63; Tot, Fe as FeO 6.76-7.89; MgO 12.17-13.98; and ZnO 3.22-4.47. ICP-MS analysis also revealed significant trace amounts of V 249 ppm, Cr 740 ppm and Ga 178 ppm. The crystallographic parameters and composition are broadly in accord with those of musgravite from the two other recorded occurrences, in Precambrian high-grade terrains in Australia and Antarctica, although mineral and rock associations in these localities differ from those in Dove Bugt. The source of beryllium in each of the musgravite occurrences is uncertain, although a metasomatic source related to granite emplacement is favoured for the occurrence in North-East Greenland.

The first results of isotopic investigations as a part of the hydrogeological study of northern Switzerland are presented. This study is part of the global geological research project of the NAGRA (National Co-operative for the Storage of Radioactive Waste) which is intended to provide the scientific knowledge required for the assessment of the feasibility of safe disposal of highly radioactive waste in the geological formations of the area. The aim of the hydrogeological research programme is to assess the natural conditions in the sedimentary sequence and the underlying granite basement, by regional investigation of hydraulic parameters, isotopic composition, and hydrogeochemistry at all existing wells (boreholes and natural thermal springs) and in 11 to 12 deep-drilled boreholes (to final depth of 1500–2500 m).

Garnets rich in manganese and iron, associated with bariumfelspars, have been reported by de Villiers from the manganese ores of Otjosondu, South-West Africa, in which they occur as the most abundant silicate mineral. The farm Otjosondu is 80 miles NE. of Okahandja, a railway station on the line between Windhoek and Walvis.

One specimen (referred to as no. 1), of which de Villiers published a chemical analysis, is massive and of a somewhat dark-yellowish colour. The material is traversed by veinlets of hyalophane (Cn9), about 0.5 mm. broad.

Paralaurionite from a new locality, the Mammoth mine, Arizona, is described. X-ray study and chemical analysis confirm the original characteristics of the mineral as described in 1899 by G. F. Herbert Smith. Measurements are given which establish new forms on crystals from Arizona and also on crystals from a South American locality. A complete angle table for twenty-eight forms is presented.

CALC-GRANULITES at Garividi are intruded by microcline granites and pegmatites. At the contacts fluorapatite, fluorian allanite, ferroan sahlite, and epidote occur; rarely, the epidote is associated with a partly metamict allanite, an analysis of which is given, also X-ray data for the unheated and heated mineral.

The significance of metastable and equilibrium pyroxene fractionation trends in tholeiitic magmas is discussed, and the development of sector zoning and skeletal growth are considered in relation to Nakamura's (1973) hypothesis of protosites on growing clinopyroxene crystal surfaces. At the Galapagos Spreading Centre (GSC) basalts and ferrobasalts investigated behave paradoxically in that the slower-cooled basalts follow the quench trend while the faster-cooled ferrobasalts define a much closer approach to the equilibrium trend.

It is concluded that under metastable conditions fractionation trends in Ca-rich pyroxenes may be strongly influenced by textural features such as cotectic crystallization of plagioclase and the onset of liquid immiscibility, the latter leading to the development of strongly Fe-enriched ferroaugites. Even under plutonic conditions metastable crystallization can develop and severely reduce the pyroxene miscibility gap. A model for metastable crystallization is presented. These considerations are then addressed to the remarkable correspondence of the Skaergaard and Thingmuli pyroxene fractionation trends.

In the eleventh volume of the Mineralogical Magazine, p. 817, in connection with the occurrence of blödite at the Mayo mines, in the Salt Range, allusion is incidentally made to a potassio-masnesian deposit, which was discovered there by Dr. H. Warth in 1878. It occurred as a lenticular stratum in the ' kallar' (impure rock salt) hand separating the Sujewal and Purwála salt beds. The material was more or less mixed up with the ' kallar' itself, and the deposit appeared to be of very limited extent.

The first occurrence of thaumasite resulting from seawater-basalt interaction has been discovered in a drill hole on Mururoa atoll (French Polynesia, South Pacific). This sulphate-carbonate-silicate is associated with zeolites (phillipsite, chabazite, gmelinite), apophyllite, analcime, and gyrolite. In this environment thaumasite can be considered as the last mineral of an alteration sequence. It crystallized from a Ca-SO3-CO2-rich and Al-Na-K-poor fluid. The temperature of this solution is unknown, but was probably not greater than 100°C.

Synthetic andradite (Ca3Fe2Si3O12) has been compressed to loading pressures >21 GPa and heated to ∼1000°C by a YAG laser in a Diamond Anvil Cell (DAC). After quenching to room temperature, X-ray diffraction of the sample, still held at 21 GPa, showed that andradite had transformed to a cubic perovskite type polymorph with a = 3.460(4) Å. Upon decompression the perovskite phase transformed into an amorphous phase. The density of the perovskite polymorph (Ca3Fe2Si3O12) is ∼13.6% greater than that of isochemical andradite at 21 GPa. Ferric iron replaces Ca2+ and Si4+ in the perovskite structure (Fe3+ + Fe3+ = Si4+ + Ca2+), giving a formula unit: (Ca,Fe3+)(Si,Fe3+)O3. The new Fe3+-rich Ca-perovskite may provide new insight into the controls on the electrical conductivity of the lower mantle.

My attention was first directed to this rock by Mr. Cruickshank, clerk of works at Beaufort Castle, in July of last year, when, from the description he gave of it, I ventured to pronounce it barytes. Specimens were soon after this put into my hands by Mr. Cruickshank, when I found that my conjecture was a correct one. There was another mineral associated with the barytes, of which we will speak afterwards. The specimens received were so very fine, that I resolved to visit the locality to be able to describe its surroundings and procure specimens for myself. This I did in May last in company with two of my colleagues and Mr. John Ross, one of Lord Lovat's gamekeepers, and who I believe was the first to call attention to this new locality.

Sakhaite from the Kombat Mine in Namibia is cubic, with a = 14.749(1)Å; the space group is a subgroup of Fd3m, the density is 2.88 g/cm3, and the index of refraction is n = 1.642(2). It is apparently more highly hydrated than previously described sakhaite, and has more aluminosilicate substitution. The idealized composition is Ca24Mg8(BO3)8[(BO3)y{AlSi4(O,OH)<16}x](CO3)8.< 8H2O with x = 0.73 and y = 5.0.

Arsenoflorencite-(La), ideally LaAl3(AsO4)2(OH)6, was studied at high pressure by single-crystal X-ray diffractometry. The unit cell was determined at nine pressures up to 7.471(8) GPa; no evidence of a phase transformation was found in this range. The pressure volume data (refined simultaneously) were fitted to a third-order Birch Murnaghan equation of state which gave V0 = 710.71(8) Å3, KT0 = 106(2) GPa and K' = 9.2(9). These values were confirmed independently from an FE–fE plot. The crystal structure was refined at 1.596, 3.622, 5.749 and 7.471 GPa, the first time this has been done for a member the alunite supergroup. The compressibility of arsenoflorencite-(La) is strongly anisotropic, with βc > βa. The main compression mechanism was found to be governed by the internal angle O3 La O2 of the La polyhedron, where the O2 and O3 atoms move toward the c axis during compression.

The diffusivity and diffusion mechanisms of hydrogen together with with deuterium and lithium, parallel to the c axis of quartz, were investigated experimentally at 800°C, 0.1 GPa with the activity of H2O or 2H2O ≈ 1 [2H is used throughout this work to describe deuterium rather than D, to avoid confusion with the diffusion coefficient, D]. The pH was set using mixtures of H2O (or 2H2O) and HCl. Three types of experiment were conducted: (1) H-in/Li-out; (2) 2H-in/H-out; and (3) 2H-in/H + Li out, using three different natural quartz crystals as starting materials. Profiles of H, 2H and Li were measured using Fourier-transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). H, 2H and Li are charge-compensated by Al3+ replacing Si4+, or by excess O2–. The total atomic concentration of monovalent cations appears to remain constant over the duration of the experiments. The resulting diffusion profiles are different for the three experimental designs and three starting materials, and some show complex shapes inconsistent with simple diffusion. A multi-site diffusion–reaction model is developed, with the theory based on previous models that have been derived mainly on the basis of conductivity measurements. In these models, the monovalent cations move away from their charge-balancing ion then diffuse rapidly to another site. The mobility of the monovalent cations is described by both a diffusion coefficient and an equilibrium constant that enables dissociation of the immobile charge-balanced defects. This model can describe complex step-shaped profiles formed in H-in/Li-out experiments, profiles with local maxima ('humped’ profiles) in 2H-in/H + Li out experiments, and error function-shaped profiles in 2H-in/H-out and previously published Li-in/H-out experiments. Our data provide support for models previously proposed for quartz. Studies of the lengths and forms of diffusion profiles from such experiments provide a useful complement to assertions from conductivity experiments.