bluuebunny/crossref_metadata_2025 huggingface dataset:
On the atomic volume relations in certain isomorphous series
Authors: Hallimond A. F.
Published: December 2006

Considerable interest attaches to the estimation of the volume occupied by the several atoms in a crystalline compound. For the complete molecule a volume can at once be calculated from the density and the chemical composition, but the further subdivision of this space into domains belonging to the constituent atoms or groups can only be made by methods that are limited and frequently very indirect. In general, the volume is not additive, and. it seems clear that the same atom may occupy very different volumes in its different compounds; indeed, it is only within the limits of a truly isomorphous series that the volume can be treated as an additive property. But even in this case it is not possible directly to calculate volumes for the constituents of the molecule if the chemical formulae are of the same type throughout; when, however, the formulae differ in type a solution may be possible.
The separation of manganese in rock analysis
Authors: Holt E. V. , Harwood H. F.
Published: December 2006

The separation and estimation of small quantities of manganese in the course of exact analysis of igneous and metamorphic rocks has long presented a difficulty. The element is almost universally present, in amounts varying from a few hundredths of one per cent. to over one per cent., the higher figure being reached in the basic rocks, especially in those rich in ferromagnesian minerals. In the ordinary course of analysis, if no special method be adopted to separate and remove manganese, this element tends to be distributed between the 'ammonia precipitate' and the lime and magnesia. It has been shown by G. Steiger that when the usual methods are employed, the manganese tends to be distributed in a quite haphazard way among the three precipitates; no definite proportion is retained by any one of them, although as a general rule most of the manganese is found with the magnesia and least with the lime.
A new model refractometer for determining the refractive indices of gem-stones, crystals, and liquids
Authors: Tully Bristow J.
Published: December 2006

The general outline and weight of the body of the instrument are devised to ensure perfect rigidity and steadiness during use, all necessary adjustments, such as the focusing of the rotating eyepiece, movement of the revolving stage, reflector, or screen, being quite independent of the optical system; which, being contained in the main body in a dust-proof receptacle, entirely prevents any vital part of the refractometer getting out of adjustment, unless deliberately tampered with.

The eyepiece, which by rotation is capable of giving a wide variation of focus, is set at the most convenient angle to ensure easy and comfortable observation.

The forward projecting portion attached to the main body is rectangular in shape, and hollow, the upper surface forming a platform in which revolves a circular plated stage with a milled edge capable of being turned about a vertical axis through 360°, with an engraved scale marked at every 45° to enable the observer to read with accuracy the least and greatest refractive indices of all doubly refracting stones.
South African occurrences of willemite. Fluorescence of willemite and some other zinc minerals in ultra-violet rays
Authors: Spencer L. J.
Published: December 2006

Willemite is a mineral of comparatively rare occurrence, but it has long been mined in New Jersey as an important, ore of zinc (Zn2Sio4, containing Zn 58.6 %), and it would seem also to be abundant in Rhodesia. In the standard mineralogies of Dana (1892) and Hintze (1889) it is mentioned from only four districts. As there is some confusion in the statement of these few localities, and further as several others have been discovered during recent years, a complete list of localities for this mineral has been compiled from the literature; and some others represented by specimens in the British Museum collection are added, inchding the African occurrences now to be described.
Place-names of mineral-localities in central Europe
Authors: Slavík František , Spencer L. J.
Published: December 2006

The place-names of mineral-localities in central Europe have presented many difficulties in connexion with the topographical indexes to 'Mineralogical Abstracts', and also in the much more extensive cardindex of localities represented by specimens in the Mineral Collection of the British Museum which has been in progress for many years. Further, I have been asked from several quarters to prepare a short check-list of equivalent names of those localities most frequently mentioned in mineralogical literature. When, in August 1927, Prof. F. Slavík was good enough to send me a copy of the manuscript list of Czechoslovakian localities and minerals which he had prepared in French for Prof. A. Lacroix for use in the Paris Museum, I at once recognized that with his co-operation a much more useful list could he prepared. This he readily assented to, and he has since extended his original list to include other countries.
On the atomic volume relations in certain isomorphous series. II
Authors: Hallimond A. F.
Published: December 2006

The isomorphous replacement of one element by another, in a pair of crystalline salts, is usually accompanied by a substantial change in the molecular volume. This progression is exceptionally well illustrated in the 'eutropic' elements K, Rb, Cs, and Cl, Br, I, which formed the subject of the first part of this paper. It was there shown that the differences produced by interchanging these elements stood in the same ratio in all the salt-series, though the size of the differences varied with the acid radicle. The object of the present note is to draw attention to the existence of similarly constant (though different) ratios for the salts of O, S, Se, Te, and for the salts of Ca, Sr, Ba. The spacings in these compounds have recently been obtained by X-ray determinations, in many cases due to u M. Goldschlnidt and his co-workers, so that it is possible to verify the rule of proportional differences in these series, although the results do not possess an accuracy so high as that of densities measured by the pyknometer.
Vote on the alkali-lavas of Mount Nimrud, Armenia
Authors: Prior G. T.
Published: December 2006

The object of this note is not to give elaborate descriptions of rocksections, but to call attention to tile fact that the old volcano of Nimrud, situated on the west side of lake Van in Armenia, was the centre of eruption of alkali-lavas presenting striking similarities to some of the alkali-rocks of the tlift Valley in East Africa.

To Dr. Felix Oswald, in his book on the geology of Armenia, we owe a detailed description of this ancient volcano, of which the vast crater, now half occupied by a deep lake, is more than five miles across. An interesting series of the lavas from the volcano was collected by Dr. Oswald and was presented by him to the British Museum. On looking over thin slices of these rocks under the microscope, I was at once struck by the surprising resemblance of some of them, with their phenocrysts of anorthoclase and scattered tufts of aegirine and the soda-amphiboles, riebeckite and cossyrite, to rocks in Prof. J. W. Gregory's collection from the Rift Valley which I had described.
The age and composition of the Whin Sill and the related dikes of the north of England
Authors: Holmes Arthur , Harwood H. F.
Published: December 2006

The system of intrusive sheets in the Lower Carboniferous formations of the north of England, familiar to geologists throughout the world as the Great Whin Sill, has a voluminous early literature which it is unnecessary to summarize here. It will be sufficient to refer to the classical papers by Topley and Lebour on the field relationships (1) and by Teall on the detailed petrography (4), each of which contains an ample bibliography of the earlier literature. The most recent general account is by Prof. E. J. Garwood (9), who contributed a careful discussion of the evidence bearing on the period of intrusion.

Teall's great paper closely followed on one devoted to some of the dikes of the north of England (3), and in it he drew attention to the remarkable petrographical Similarity between the rocks of the Heft and High Green dikes and that of the Whin Sill (4, p. 656).
The optical orientation of labradorite from County Down (Ireland) determined by the Fedorov Method
Authors: Smith W. Campbell
Published: December 2006

Labradorite of exceptional purity, occurring as phenocrysts in two basaltic dikes just below the lighthouse at St. John's Point, Ardglass, County Down, Northern Ireland, was described by Professor A. Hutchinson and myself in 1912. The refractive indices for sodium-light were determined on an Abbé-Pulfrich total-reflectometer. Carefully selected material was analysed by Mr. G. G. Knighton and by Mr. M. C. Burkitt, and the specific gravity of the material analysed was determined.
Inclusions in the apatites of some igneous rocks
Authors: Groves A. W. , Mourant A. E.
Published: December 2006

In a recent paper by Dr. W. F. Fleet and Dr. F. Smithson attention was drawn, to the occurrence of dark apatites and apatitcs with dark cores of inclusions in certain sediments of the Midlands of England, and it was pointed out that the only other definite occurrences known of these peculiar apatite grains in either igneous or sedimentary rocks appeared to be restricted to the Old Red Sandstone of the Cardiff area, the ‘newer’ granites of Jersey, and the Leinster granite. These writers also expressed the hope ‘that any future observation of such grains may be recorded with a view to tracing the source of the detrital grains of Welsh and English rocks’.
A relation between the density and refractive index of silicate glasses, with application to the determination of imitation gem-stones
Authors: Bannister F. A.
Published: December 2006

It has long been possible to identify readily many minerals by means of density and refractive index determinations, and the chemical composition also can often be approximately deduced. Tilley has shown that it is practicable to determine any natural glass by this method and be succeeded in separating the natural glasses into groups characterized by certain limits of specific refractivity. As far as the author is aware, no such systematic method has been described for distinguishing the artificial glasses one from the other, and it is these glasses that we are concerned with in attempting to determine the approximate composition of an imitation gem-stone without the aid of chemical analysis.
The meteoric stone of Lake Brown, Western Australia
Authors: Prior G. T.
Published: December 2006

The discovery of the meteoric stone near Lake Brown, County Avon, South-West Division, Western Australia, was recorded by Dr. Edward S. Simpson in the Annual Progress Report of the Geological Survey of Western Australia for 1921 (1922, p. 53). The following details concerning the meteorite are taken from that report and from a letter of September 25, 1925, sent by Dr. Simpson with the specimen, weighing 174 grams, which was presented to the British Museum collection by Mr. A. Gibb Maitland, at that time Government Geologist of Western Australia.
On the occurrence of native gold at Hope's Nose, Torquay, Devonshire
Authors: Russell Arthur
Published: December 2006

Some thirty-five years or so ago small quantities of free gold were found in calcite in or near a crush-breccia filling an east and west fault, in the patch of Middle Devonian limestone which forms that portion of the coast known as Daddy Hole Plain directly south-east of Torquay. The name of the actual discoverer I have been unable to ascertain, neither do any specimens appear to have been preserved ; but the late Mr. T. Harrison, the then proprietor of the Queen's Hotel, Torquay, and several other persons subscribed about s and a small amount of prospecting work was carried out, apparently with little result. The only reference to this discovery which I know of is a brief one in 'The geology of the country around Torquay' (Mere. Geol. Survey, 1903, p. 48). To Mr. B. W. Stedham of Torquay I am indebted for the additional particulars given and also for pointing out to me the exact spot, which is on the side of a fissure formed by a large pinnacle of rock standing away from the cliff below the old quarry.
A new occurrence of zunyite near Postmasburg, South Africa
Authors: Nel Louis T.
Published: December 2006

While I was engaged on the geological survey of the Postmasburg manganese fields during 1927 the rare mineral zunyite, a basic orthosilicate of aluminium, was discovered in some altered highly aluminous shales or flagstones. The only occurrence of zunyite so far known is in Colorado, where, according to Dana's ‘System of Mineralogy’, it was found at the Zuñi mine, Anvil Mountain, San Juan Co., and near Red Mountain, Ouray Co.
Some mineralogical and chemical changes induced by progressive metamorphism in the Green Bed group of the Scottish Dalradian
Authors: Phillips F. Coles
Published: December 2006

The petrology of the igneous rocks has for the last quarter of a century been established,on a sound quantitative basis, largely as a result of the body of experimental work available on silicate melts. In the field of metamorphism, however, progress has been much less marked, and the difficulties of the laboratory development of stresses comparable with those acting during regional metamorphism must for some time leave our knowledge of the crystalline schists far behind that even of the hornfelses. A quantitative approach, however, is not confined to the experimental side. The introduction of the conceptions of facies and grade raises a new need for exact knowledge of the compositions of the various minerals, both of those constituting the different isophysical assemblages of a given grade, and of the isochemical assemblages representing a given rock under the grade-conditions of the various facies established.
Notes on British barytes
Authors: Sweet Jessie M.
Published: December 2006

When the slip catalogue of the barytes specimens in the British Museum collection was in the course of preparation, a few observations were made which may be of sufficient importance to place on record.

The lists of localities of the barium minerals, barytes, witherite, alstonite, and barytocalcite, in the collection show that rather more than half of the specimens (573 out of 975) come from the British Isles. Hence it would seem that there is a special concentration of these minerals in this part of the world. Possibly this is fictitious, as the collection cannot be considered to be completely representative.
On face- and zone-symbols referred to hexagonal axes
Authors: Hey Max H.
Published: December 2006

The axial system of Bravais, with three co-planar axes at 120°C to one another and a fourth at right angles to them is almost universally adopted for the description of crystals based on the hexagonal prism as unit cell. But it does not seem to have been generally recognized that the use of these axes entails some complications in respect of face- and zone-symbols. These it is the purpose of the present note to consider.
Cupriferous melanterite from the Skouriotissa mine, Cyprus
Authors: Hey Max H.
Published: December 2006

A Magnificent specimen of melanterite has recently been presented to the British Museum by the generosity of Mr. James L. Bruce, Resident Director of the Cyprus Mines Corporation, through the agency of Prof. C. Gilbert Cullis of the Royal School of Mines, London. The specimen (B.M. 1930,439) appears to merit a short description, for it cons,ists of a group (35 by 25 cm.) of enormous greenish-blue crystals (up to 18 by 13 cm.) of a very unusual habit, being tabular to b(010). The photograph (fig. 1) can convey only a very inadequate idea of the beauty of the group, and it is most fortunate that the generous action of Mr. Bruce and the care of Prof. Cullis have ensured its preservation and exhibition for the pleasure of many.
A contribution to the study of moonstone from Ceylon and other areas and of the stability-relations of the alkali-felspars
Authors: Spencer Edmondson
Published: December 2006

Ceylon moonstone is probably the best known variety of those alkali-felspars which display a prominent internal colour reflection or ‘schiller’. On account of its blue sheen and its clear transparency, the mineral has attained a certain degree of popularity and some value as a gem-stone.
A tholeiitic phase of the quartz-dolerite magma of central Scotland
Authors: Walker Frederick
Published: December 2006

The Permo-Carboniferous quartz-dolerites of central Scotland are generally holocrystalline, and only two intrusions amongst them with a fresh vitreous base have been recorded—those of Dalmeny in West Lothian, andKinkellnear Kirkintilloch (northof Glasgow). Both rocks have already been described briefly, but in view of their many interesting features a more thorough treatment seems desirable, particularly as they have a bearing on some recent theories of magmatie differentiation advanced by Dr. C. N. Fenner.
An occurrence of grunerite at Pierrefitte, Hautes-Pyrénées, France
Authors: Warren Harry V.
Published: December 2006

As grunerite is a somewhat uncommon mineral, and as its occurrence at Pierrefitte in association with lead and zinc ore is unusual, if not unique, it may be worth while to put on record the following notes on some material which I collected during an examination of the Pierrefitte deposits.

The name 'grunerite' was originally given to a fibrous mineral approximating in composition to FeSiO3 and occurring with magnetite and garnet at Collobrières in the dept. of Var, in the south of France, which was described by Gruner in 1847. It was originally supposed to be a pyroxene, but was later shown by Des Cloizeaux and Lacroix to belong to the amphibole group. A similar mineral occurs in the iron deposits of the Lake Superior district, and elsewhere ; but it has not been recorded from the Pyrenees.
On pink epsomites and fauserite
Authors: Hey Max H.
Published: December 2006

In 1865 A. Breithaupt described a new mineral from Herrengrund, Hungary, to which he gave the name of fauserite. It formed very pale pink crystalline aggregates and prismatic crystals, with prism angle near 88°42′ (over a), apparently orthorhombic, and cleavage b(010). Two other prisms with angles (over a) 54°39′ and 107° 50′ were observed, and a pyramid p, giving mp= 52° ; these would correspond to forms (210), (340), and (111), and the angles are near those of epsomite. An analysis by Mollnár gave the figures shown under I below—a magnesium and manganese sulphate hexahydrate, with the molecular ratio MgSO4(Mn,Mg)SO4 = 31.62 %. There is no evidence that the analysed material (stated to be crystalline) was homogeneous.
The residual liquids of crystallizing magmas
Authors: Fenner Clarence N.
Published: December 2006

In the Mineralogical Magazine for September, 1930, Dr. Frederick Walker describes 'A tholeiitic phase of the quartz-dolerite magma of central Scotland'. Several pages of the article are devoted to a consideration of the phenomena he has observed in these rocks in their bearing upon certain views which I have expressed. In most respects Dr. Walker has clearly grasped the essential features of my thesis, and his efforts to obtain further information on the various points have been well directed. I am glad to welcome such a discussion as he has given, even though his conclusions are somewhat opposed to mine. In one respect, however, he has apparently overlooked an essential feature of my argument. On this matter, and on some points of evidence given, I should like to present some discussion. I desire also to examine certain other recent papers by Daly and Barth and by Bowen, Schairer, and Willems, in which the views expressed in my article have met with some criticism.
A chemical, optical, and X-ray study of nepheline and Kaliophilite
Authors: Bannister F. A. , Hey M. H.
Published: December 2006

Correlated data prove the approximate constancy of the number of oxygen atoms in the unit cells of several nepheline and elaeolite specimens. Thence the number of atoms of each kind per unit cell have been counted. The cell-volumes and optical properties have slso been correlated with the chemical composition. An approximate structure is suggested which, together with the chemical work, explains the variable composition of nepheline. The contents of the unit cell may be written Si16−nAln(Na,K,½Ca)nwhere n ranges from 6.6 to 8.2. Kaliophilite is shown to possess a much larger cell than that of nepheline, and its Lauegram exhibits higher symmetry. 'Pseudonepheline' (rich in potassium) has a slightly greater cell-volume than normal nepheline, but its Lauegram is almost identical and its axial ratio only slightly less.
The crystal-structure of the bismuth oxyhalides
Authors: Bannister F. A.
Published: December 2006

A. De Schulten published a crystallographic and optical investigation of the bismuth oxyhalides in 1900. He succeeded in preparing minute square plates capped with pyramidal planes, but evidently the difficulties of manipulation prevented the measurement of interfacial angles. He did, however, record a negative uniaxial figure observed in a direction perpendicular to the plane of the square plates of all three salts BiOCl, BiOBr, and BiOI. The present work was undertaken to extend A. de Schulten's observations, to measure the axial ratios, and to determine the crystal-structure.
Two new bismuth minerals from South Africa
Authors: Mountain Edgar D.
Published: December 2006

A small specimen (McGregor Museum, no. 4465) labelled ' Bismuth ore' was sent to me in 1932 by Miss M. Wilman, Curator of the McGregor Museum, Kimberley, for identification. It had been presented to the Museum by Mr. M. Caplan, a store-keeper of Steinkopf. The majority of bismuth-bearing minerals from Namaqualand come from a number of spots in the neighbourhood of the water-hole known as Jackals Water, which is situated 18 miles NNE. of the village of Steinkopf. Reference has already been made to this locality in a previous paper. The exact locality of this specimen is a pegmatite outcrop in granite-gneiss about a mile and a half south of the Noumaas trigonometrical beacon which is situated some 13 miles north-west of Jackals Water to the west of the Viool's Drift road. The specimen was picked up on the surface, being obviously of eluvial origin.
The rôle of kyanite in the ' hornfels zone' of the Carn Chuinneag granite (Ross-shire)
Authors: Tilley C. E.
Published: December 2006

The metamorphism surrounding the granite of Carn Chuinneag in eastern Ross-shire provides the classical example of polymetamorphism in which a regional metamorphism is superimposed on a normal thermal metamorphism.

Prior to the regional alteration a pelitic facies of the Moine sediments suffered metamorphism of a purely thermal type in the vicinity of the granite. At a subsequent date the whole region was involved in fold movements with the production of crystalline schists. In this deformation the belt of rocks surrounding the granite yielded in such a way that belts of the hornfels zone moved en masse and are preserved amidst rocks which are now typical crystalline schists, and all stages of transition between genuine hornfelses and typical micaschists can be traced in the field.
Some data on the iron-rich hypersthenes
Authors: Henry N. F. M.
Published: December 2006

The first iron-rich hypersthene reported was from Vittinki in Finland and was described by M. Saxén in 1925. In 1932 N. Sundius showed that the so-called 'iron-anthophyllite' from Tunaberg in Sweden was really a very iron-rich hypersthene. He suggested that two other 'iron-anthophyllites' occurring similarly in the eulysites of Sweden at Bygdsiljum and at Mansjö might also prove to be really iron-rich hypersthenes.

Here chemical and optical data are given for the Mansjö mineral which fits well into the series and proves to be slightly richer in iron than the Tunaberg one. Data are also given for hypersthenes from Loch Duich and from Glen Buchat in Aberdeenshire, while, thanks to the kindness of Professor P. Eskola, it has been possible to obtain a sample of the Vittinki mineral and to complete the data of M. Saxén.
Studies on the zeolites. Part VIII. A theory of the vapour pressure of the zeolites, and of the diffusion of water or gases in a zeolite crystal
Authors: Hey Max H.
Published: December 2006

The behaviour of the zeolites on dehydration, and their capacity for absorbing other gases and vapours in place of the water removed, have formed the subject of numerous investigations, qualitative and quantitative, of various degrees of accuracy. In only a few cases have attempts been made to fit an equation to the experimental data. Of these equations, those proposed by O. Weigel, G. F. Hüttig, and O. Schmidt are quite inadequate, as is readily seen by a trial with the more extensive data now available. On the other hand, E. Rabinowitsch derived an equation which proved capable Of reproducing the experimental data and is very similar to the equation now proposed, but derived in a quite different way.
A critical review of the data for a revision of the enstatite-hypersthene series
Authors: Walls Ronert
Published: December 2006

At the suggestion of Professor H. H. Read the optic axial angle and the refractive index y were measured in four hypersthenes from Aberdeenshire norites. As the values obtained suggested that the minerals were iron-rich, it was decided to have chemical analyses made. These and the optical data are set out in table I below. At the same time the literature has been searched for analyses and optical data of enstatites and hypersthenes, in order to supplement those used by A. N. Winchell in his diagram of variation of the properties of the series. The references given by Winchell have been examined, and it is found that some of the data is not reliable.
Anomalies in the analytical determination of water in epidote
Authors: Smethurst A. F.
Published: December 2006

Numerous veins and veinlets of epidosite traverse the crystalline schists and associated igneous rocks of the Malvern complex. They art fine-grained, compact rocks, of uniform texture and pale greenish-yellow colour, and vary in composition from almost pure epidote to mixtures of epidote with small quantities of quartz, sphene, sericitic mica, apatite, and, in almost insignificant amount, albite.

Analytical investigation of these rocks revealed the fact that the epidote they contain holds its water more tenaciously than has hitherto been suspected : the determination of water-content by the methods usually applied to the analysis of rocks and minerals gave results which were so seriously low as to suggest that the mineral was essentially anhydrous. Though more drastic methods increased the yield considerably, they failed to liberate more than about 75 % of the amount of water which, theoretically, should be present.
Variability of garnet in granites
Authors: Brammall A. , Bracewell S.
Published: December 2006

IN extending earlier work on the distribution and significance of manganiferous garnet in the Dartmoor granites, the senior author found it necessary to determine whether the average composition of the Dartmoor species was fairly represented by the single complete analysis (II, below) hitherto available - that of an aggregate of garnet fragments separated from crushed tor-granite.

As a preliminary step a similar aggregate from the cordierite-rich granite exposed in the Sweltor quarry was analysed (I).
Biographical notices of mineralogists recently deceased. (Sixth series.)
Authors: Spencer L. J.
Published: December 2006

In the following list of 36 lives, with a range in ages frdm 56 to 89, the average age is 71.0 years. The average of 460 lives noticed in this Magazine since 1877 is 65.9 years ; and in the six numbers of this series since 1919 there has been a gradual and steady increase from 63.6 to 71.0.

Particulars respecting Czech, Italian, Japanese, and Russian subjects have been kindly supplied by Professors F. Slavlk, G. R. Levi, R. Ōhashi, and Mr. S. I. Tomkeieff respectively, and to these colleagues I express my thanks.
Notes on the occurrence of wulfenite at Brandy Gill, Cumberland, and of leadhillite at Drumruck mine, Kirkcudbrightshire
Authors: Russell Arthur
Published: December 2006

In October 1875 the late J. G. Goodchild recorded his then recent discovery of a mineral which he stated 'he believed' to be wulfenite and which he had found on an old mine dump near Carrock Fell, Troutbeck, Cumberland. One specimen only was, I believe, found by Mr. Goodehild, and this he presented to the Carlisle Museum, where it has been seen by myself, the label bearing the more precise locality of Brandy Gill.
Eulysites and related rock types from Loch Duich, Ross-shire
Authors: Tilley C. E.
Published: December 2006

Our knowledge of the rare rock type eulysite (A. J. Erdmann, 1846) comes almost wholly from Swedish occurrences amt hitherto no examples have been recognized from Britain. It is therefore of interest to place on record a new Occurrence of eulysites and related rocks from among Lewisian rocks of the Glenelg area, Scotland.

The rocks shortly to be described come from the vicinity of Totaig on Loch Duich between Totaig and Letterfearn, little more than half a mile from the first described occurrence of eclogite in Britain. These eulysitic rocks crop out on the hillside immediately south-west of Druideig Lodge. About 200 yards south-west of the lodge coarse garnet-paragneisses form outcrops associated with grunerite- and cummingtonite-garnet-gneisses, and a similar interbanded association is found at higher levels.
Two new meteoric stones from South Australia—Lake Labyrinth and Kappakoola
Authors: Spencer L. J.
Published: December 2006

The recovery of these two meteoric stones is due to the energy and resource of Mr. R. Bedford of the Kyancutta Museum, South Australia. They have been sent by him for description and placing on record, and he has very kindly allowed portions to be retained for the British Museum collection of meteorites. I also owe my thanks to him for the detailed information he has supplied respecting the finding of the specimens.
Transfusion of quartz xenoliths in alkali basic and ultrabasic lavas, south-west Uganda
Authors: Holmes Arthur
Published: December 2006

The occurrence in basic lavas of quartz xenocrysts and xenoliths and the various types of reaction phenomena which they exhibit have been well described by Lacroix (1893, pp. 17-48). The modified quartz is often surrounded by a zone of pyroxene granules or prisms and on the inner side of this zone the quartz may be replaced by glass, both peripherally and through an anastomosing system of vein-like channels. The glass may be clear or charged with gas inclusions; some examples contain minute quartz-pseudomorphs after tridymite, while in others microliths of alkali-felspar occur. In the basanitoid of Hirzstein, Hesse, nepheline occurs around quartz in place of the usual vitreous shell (Fromm, 1891, pp. 58, 65, and 70). Despite these observations, it seems to have been tacitly supposed that the glass is a more or less hydrous variety of vitreous silica.
An occurrence of greenalite-chert in the Ordovician rocks of the southern uplands of Scotland
Authors: Kennedy W. Q.
Published: December 2006

Rocks composed mainly of the hydrated ferrous silicate greenalite are of very restricted geological and geographical distribution and, up to the present, have been recognized only from certain of the pre-Cambrian sedimentary iron-bearing formations of the Lake Superior region. It is of interest, therefore, to record an additional occurrence, not only from another region but from a later geological system.
The composition and paragenesis of the biotites of the Carsphairn igneous complex
Authors: Deer W. A.
Published: December 2006

The Cairnsmore of Carsphalrn igneous complex (1) is the smallest of the larger Caledonian intrusions of the Southern Uplands of Scotland. The intrusion is composite, consisting of a central granite, followed by successive zones of granite-tonalite hybrid, tonalite, and basic hybrids. The complex began with the intrusion of a gabbro. When this was crystallized, but still at a high temperature, the tonalite was emplaced. This intrusion of tonalite produced a series of hornblende-hybrids. The hybridization of the original gabbro attendant on the injection of the tonalite is the result of a 'partial magma' of potash-felspar, quartz, and volatiles. The final intrusion of granite took place while the tonalite was still incompletely crystallized, and resulted in the formation of a zone of acid hybrid rocks. The three biotites that have been analysed occur in the granite, tonalite, and hornblende-hybrid respectively.
The tektite problem
Authors: Spencer L. J.
Published: December 2006

The natural glasses, found as small corroded pieces scattered on the earth's surface and in alluvial deposits in a few limited areas, have long presented a puzzling problem; and many theories have been propounded to explain their origin. They have been known in southern Bohemia and western Moravia since before 1787; and similar material has since been found in the Dutch East Indies, Malay States, Australia, Tasmania, French Indo-China, south China, Philippine Islands, and quite recently in the Ivory Coast in West Africa [M.A. 6-106]. These glasses are distinct in chemical composition from volcanic glass (obsidian), and there are no volcanoes in the districts where they are found. They have been given the names m oldavites, billitonites, austral ites, Darwin glass, indoch inites, rizalitcs [M.A. 4-422; 6-403], &c.
An iron-rich optically-positive hypersthene from Manchuria
Authors: Tsuru Kazuo , Henry N. F. M.
Published: December 2006

In a recent paper the occurrence was described of a very iron-rich orthorhombic pyroxene in thermally metamorphosed iron-rich rocks in Manchuria. The crystals are commonly 2-5 cm. in length, but some are larger, and they are accompanied by grunerite, small garnets, and disseminated magnetite. Some of these crystals are optically positive, and the following data were obtained on one crystal.
An occurrence of the mineral pumpellyite in the Lake Wakatipu region, western Otago, New Zealand
Authors: Osborne Hutton C.
Published: December 2006

Previous accounts of pumpellyite, a blue-gree n hydrous silicate of calcium and aluminium, are few in number; the first record is that of Palache and Vassar, who described the mineral after a study of the amygdaloidal rocks of the Keweenaw Peninsula. Later Burbank recorded a very similar occurrence in Haiti, West Indies. Again, it was observed as a constituent of veins cutting glaucophaneschists in California by Irving, Vonsen, and Gonyer, and later by Waldmann at Hochlantsch Mount, Styria, in an altered diabase, and from Lake Enare, Finnish Lapland, where it occurred in altered lime-silicate rocks. Pumpellyite was found by Quitzow in diabaseporphyrites and glaueophane-rocks from the Trias of northern Calabria, Italy.
The deuteric mineral sequence in the Enoggera granite, Queensland
Authors: Whitehouse Marjorie J.
Published: December 2006

The Enoggera 'granite', in which occur the minerals to be described, is situated a few miles to the west of the city of Brisbane, and within the Greater Brisbane area. Deuteric and allied minerals have previously been recorded from quarries in the granite by H. C. Richards and W. H. Bryan, and a specimen is recorded ill the Queensland Mineral Index as 'Heulandite occurring as geodes in granite. Loc. Enoggera.'

The granite itself is very varied in character, and Bryan has recognized two main types, a pink phase and a grey phase. The pink phase approaches an adamellite, while the grey is more granodioritic in character. There is, however, every gradation from one type to the other due to admixture, and this reaches its maximum in a hybrid rock formed presumably by the mingling of the two magmas.
Wollastonite solid solutions from Scawt Hill, Co. Antrim
Authors: Tilley C. E.
Published: December 2006

Wollastonite at Scawt Hill, Co. Antrim, ocours as a constituent of both the exogeneous and endogeneous contactzones of the dolerite. In the former it is associated only with flint nodules in the metamorphosed chalk, in the latter, however, commonly as a minor constituent of certain of the hybrid types.

In my original account a wollastonite-bearing augite-dolerite from this latter zone was figured without further description in the text (plate xvII, fig. 3). In examining the optical characters of wollastonites associated with hedenbergite, I had occasion to turn again to the wollastonites of this particular rock type.

As indicated in the explanation of the figured section (loc. cir., p. 467), the dolerite is built essentially of sharply zoned brown titanaugite, labradorite, wollastonite, iron-ores, interstitial thomsonite, analcime, and accessory sphene. In this aggregate wollastonite forms subidiomorphic crystals averaging 1 ram. in size, and from a series of sections its predominant forms can be readily made out.
On some unusual twin-laws observed in the orthoclase crystals from Goodsprings, Nevada
Authors: Drugman Julien
Published: December 2006

The very abundant literature dealing with the twinning of felspar phenocrysts has put on record a surprisingly large number of twin-laws. Some of these have such complex indices that they have never been accepted; others are regarded as doubtful. Yet the authors of these have well-established reputations and the accuracy of their observations cannot be doubted. The difficulty lies in the interpretation of the results. Beside numerous examples of well-defined laws, one comes across a high percentage of isolated cases, each appearing quite as plausible as these, yet difficult to assign to any definite law.
A review of the data of the Mg-Fe-clinopyroxenes
Authors: Henry N. F. M.
Published: December 2006

In recent years several occurrences of clinoenstatite and of clinohypersthene have been recorded, the identification depending on the oblique extinctions measured from a prominent cleavage. This is, of course, quite inconclusive, because many sections of hypersthene show extinction-directions oblique to the trace of a prominent cleavage, and much fuller data would be necessary before most of these occurrences could be accepted as monoclinic Mg-Fe-pyroxenes.
On the occurrence of acmite in the riebeckite-microgranite of Mynydd Mawr, Caernarvonshire
Authors: Nockolds S. R.
Published: December 2006

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.’
On the nature of withamite from Glen Coe, Scotland (With Plate IV.)
Authors: Osborne Hutton C.
Published: December 2006

In 1824 Henry Witham discovered a beautiful red epidote mineral in the lavas of Glen Coe, Argllshire, which was described by Brewster under the name withamite. An analysis was made by Coverdale of obviously highly impure material, but later a more complete one was carried out by Heddle on carefully hand-picked mineral. Heddle admits, however, that his analysis shows ‘by no means a satisfactory agreement with the composition of epidote’, and from his figures it would seem very likely that his analysed material was also impure. In the Glen Coe Geological Survey Memoir no further data were recorded of this mineral, Heddle's analysis and description merely being quoted.

The writer visited Glen Coe and collected material in a cutting on the new road, approximately 5½ miles west of King's House (Geological Survey, sheet 53), where it is fairly well exposed. It occurs in a fine-grained, rather altered andesitic rock, as narrow veinlets up to 120 mm. in length and 50 mm. in width ; also as infillings of vesicles. The veinlets may be straight or highly irregular; in the former case they possibly follow joint-planes, for the rock will often fracture along such a plane, producing one or two surfaces covered with the red epidote mineral. The vesicles vary greatly in size from approximately 0·3 to 70 mm., and in the larger ones calcite is a common associate.
Tabular spessartine crystals in muscovite
Authors: Mountain Edgar D. , Kent Leslie E.
Published: December 2006

During the course of a survey of the mineral deposits of the area immediately south of the Murchison Range in the NE. Transvaal, a visit was paid to the Union mica mine, one of the only two producing mica mines in South Africa. Interest very soon centred round the occurrence of flattened garnet inclusions in a large number of the mica sheets inspected in the trimming hut. A description has been given by A. L. Hall of the nature of the occurrence of the muscovite, while the geology of the area surrounding the mine is shown in a general way on his map. However, no mention was made of platy garnet crystals; and the Union mine is shown on the map as the Premier mica mines, a name by which it was then known. It is situated on the farm Inyoko (or Inyoka) (24° 8' 25" S., 30° 50' 49" E.) on the western slopes of a ridge overlooking the Sandspruit valley, and lies only two miles from Mica Siding on the Selati Railway, though best approached from Gravelotte by road, a distance about 22 miles.
On the atomic arrangement and variability of the members of the montmorillonite group (With Plate V.)
Authors: Nagelschmidt G.
Published: December 2006

According to their atomic arrangement the minerals found in clays can be divided into the two-layer and the three-layer structures. The members of the first group have alternating silica and alumina layers, e.g. kaolinite; the members of the second group have one alumina (or magnesium or iron) layer between two silica layers, e.g. pyrophyllite. The clay minerals can also be classified into two groups according to their power to diffract X-rays. The first group gives good powder photographs with twenty to forty well-developed lines if copper or iron radiations are used, whereas the second group gives poor diagrams with only a few lines, usually under fifteen, some of which are wide and indistinct. Exposure times for the second group are about two to three times as large as those for the first group. The poor diffracting power for X-rays may be due either to a lack of regularity (‘roughness’) of the lattice, or to an extremely small size of the single crystallites. It is possible that both effects are aetive to some extent, but the lack of regularity of the lattice is probably the main reason. Neither the microscopic evidence nor sedimentation data based on Stokes's law show these minerals to have particles smaller than 10-6 cm., though it is possible that the optical effects such as double refraction are due to aggregation, and it is clear that the equivalent radius is an unsatisfactory measure for plate~shaped particles. Both classifications are shown on p. 141.
A chemical and optical study of a low-grade metamorphic actinolitic amphibole from Coronet Peak, western Otago, New Zealand
Authors: Hutton C. Osborne
Published: December 2006

This amphibole is an important constituent of an albite-epidote-actinolite-chlorite-calcite-schist from the summit of Coronet Peak in the Wakatipu district, western Otago. The mineral is somewhat concentrated into folia and porphyroblastie crystals up to 5·0 mm. in length, and is markedly flattened parallel to the orthopinakoid so that sections cut parallel to the schistosity exhibit numerous porphyroblasts, deeply coloured, poorly birefringent, and showing rather poor cleavage lines (fig. 1 A and B; fig. 2 A). In slices cut across the foliation numerous elongated end-sections are to be seen with development of small orthopinakoids (fig. 2 B).

The refractive indices (±0·002) are α 1·635, β 1·650, γ 1·655; γ—α 0·020. The angle γ:c = 18° and 2V 60°±1° Pleochroism follows the scheme α pale yellow, β dirty bluish-green, γ deep bluish-green, with absorption γ > β > α.
An X-ray examination of mordenite (ptilolite)
Authors: Waymouth C. , Thornely P. C. , Taylor W. H.
Published: December 2006

The structures of the fibrous zeolites edingtonite, thomsonite, and natrolite (with scolecite and mesolite) were determined by X-ray methods some years ago, and it was suggested shortly afterwards by M. H. Hey and F. A. Bannister in a private communication to one of us (W.H.T.) that ‘ptilolite’, another zeolite of fibrous habit, might prove to have a similar structure. An X-ray rotation photograph about the needle axis indicated a unit-cell dimension along the needle axis of approximately 7·5 Å., quite different from the axis c 6·6 Å. characteristic of the fibrous zeolites previously examined, and no further examination of ‘ptilolite’ was made at that time. We have now determined the unit cell and space-group of this crystal, and further work is in progress with a view to the complete analysis of the structure. This paper presents an account of the experimental data which we have obtained.
The leaching of granite and some other rocks
Authors: Davison E. H.
Published: December 2006

In 1913 the late Mr. J. J. Beringer suggested that it would be of interest to determine the solubility of crushed felspar (a) in distilled water free of carbon dioxide, and (b) in distilled water saturated with carbon dioxide. For this purpose crushed felspar (orthoclase) was covered with water in a silica basin (i) in a desiccator containing potassium hydroxide solution, and (ii) in a desiccator connected with a carbondioxide Kipp's apparatus. These were allowed to stand for a fortnight and the alkalinity of the water Was then determined by N/100 hydrochloric acid. This experiment was continued until the end of July, 1914. A definite solubility was determined in each case and the solubility in the carbon dioxide water was only slightly more than in the water free from carbon dioxide. Unfortunately Mr. Beringer died early in 1915, and the records of his experiment could not be found.
The composition and paragenesis of the hornblendes of the Glen Tilt complex, Perthshire
Authors: Deer W. A.
Published: December 2006

The south-eastern margin of the Glen Tilt complex consists of a long strip of diorites with a number of small associated patches of rocks of appinitic type. Xenoliths, both of hornblendite and hornblendeschist, the latter belonging to the Perthshire series of the Dalradian, are found enclosed within the dioritic rocks, which range petrographically from diorite to quartz-mica-diorite. In all these rocks hornblende is the most important fcrromagnesian constituent always predominating over pyroxene in the basic members and frequently persisting to the exclusion of biotite in the intermediate rocks of the intrusion. The hornblendes were examined chemically because of the difficulty of estimating their composition even from a thorough optical investigation. As they play such an important role in the complex it is considered that they may give some indication of the history and mode of formation of the rocks in which they occur. Such a chemical investigation of a series of related hornblendes will also indicate the possible range of composition of common amphiboles within the diorites and related rocks of a single complex.