bluuebunny/crossref_metadata_2025 huggingface dataset:
The significance of clay minerals in studies of the evolution of the jurassic deposits of the Betic Cordillera, SE Spain
Authors: Delgado I. Palomo , Huertas M. Ortega , Hach-Ali P. Fenoll
Published: December 2006

A detailed study of the mineralogy of the Jurassic detrital sediments of the Betic Cordillera (SE Spain) was needed to resolve problems relating to the environment of deposition. The choice of the marly limestone and marl facies for such a study was appropriate, because these are well represented throughout the Cordillera and consist of the earliest materials deposited after the break-down of the Liassic carbonate platform. Quantitative mineralogical analyses and crystallochemical studies enabled the source area to be defined, as well as indicating the likely erosion and weathering processes undergone by the minerals during transport and deposition, and the degree of diagenesis. Four mineral associations were distinguished, permitting a temporal and spatial analysis of the environment of deposition, and the relationship between its mineralogy and the different lithological facies.
Physico-chemical characterization of Cu2+-exchanged sepiolite
Authors: Corma A. , Pérez-Pariente J. , Soria J.
Published: December 2006

Copper-sepiolites exchanged at different levels have been studied by ESR, IR, and TG. The results indicate that in the unheated samples the Cu2+ ions are located in octahedral edge positions. After dehydration, the Cu2+ ions occur in two positions with different environments. Some of the Cu2+ ions lose the two molecules of coordinated water in one step, at low dehydration temperatures, and adopt a square pyramidal geometry. Other Cu2+ ions lose the coordination water in two steps, at lower temperature than the natural sepiolite, and adopt a tetrahedral symmetry.
29Si- and27Al-MAS/NMR study of the thermal transformations of kaolinite
Authors: Watanabe T. , Shimizu H. , Nagasawa K. , Masuda A. , Saito H.
Published: December 2006

Thermal transformations of kaolinite were studied by29Si- and27Al-MAS/NMR and ESR techniques. In metakaolin, Si is still dominantly in theQ3state (three Si atoms bonded to an Si-O4tetrahedron) and Al detectable by NMR is in both 4-coordination and 6-coordination. Coordination polyhedra around Al or Fe replacing Al are much distorted. Metakaolin crystallizes into γ-alumina and mullite exothermically at ∼980°C, this crystallization being preceded by a faint endothermic reaction. The latter is due to segregation of SiO2and Al2O3, which results in an increase of Si in theQ4state and an increase of 6-coordinated Al2O3.
Simulation of soil reactions: aluminium-iron(III) hydroxy species react with silica to give deposits on particle surfaces
Authors: Taylor R. M. , Raupach M. , Chartres C. J.
Published: December 2006

In solutions of three different, stable, Al-Fe(III) hydroxy species, reaction with silica particles for one month decreased the solution pH and gave deposits containing Fe, Al and Si over the surfaces of the particles, joining them together. Infrared difference spectroscopy showed the deposits to be similar to imogolite or feldspathoid phases, depending on the composition of the initial solution. Comparative SEM and EDXA elemental analysis profiles supported the conclusion that these laboratory products were similar to naturally occurring soil cementing agents. An explanation is given for the observed reactions and the formation of materials likely to act as cementing agents in soil.
27Al Satellite Transition MAS-NMR Spectroscopy of Kaolinite
Authors: Rocha J. , Pedrosa De Jesus J. D.
Published: December 2006

Highly crystalline kaolinite has been studied by 27Al satellite transition magic angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. This technique provides an additional narrowing of the MAS spectral lines by a factor of more than three compared with the width of the prominent central transition. Evidence for the presence of two crystallographically inequivalent hexacoordinated Al sites has been found. The results support the kaolinite crystal structure proposed by Bish & Von Dreele (1989).
Fluid composition, mineralogy and morphological changes associated with the smectite-to-illite reaction: an experimental investigation of the effect of organic acid anions
Authors: Small J. S.
Published: December 2006

The smectite-to-illite reaction (illitization) was examined in a dilute suspension of Wyoming bentonite in the presence of oxalate and acetate. Experiments were performed using fluidsampling apparatus at 200°C, 50 MPa, in which progressive changes in both clay mineralogy and fluid composition were monitored. The presence of K-oxalate and K-acetate under neutral-alkaline conditions produced significant reaction of smectite to either R1 or R2 ordered illite-smectite with 60–70% illite layers. Experiments at the same temperature with KCl, or oxalic acid plus KCl, produced no reaction. Fluid chemistry showed that K-oxalate and K-acetate resulted in the establishment of aK+/aH+ conditions within the muscovite stability field, favouring the formation of illite. The extent of dissolution and precipitation indicated by fluid data is insufficient to account for the amount of illitization evident in the mineralogy. This implies that a localized dissolution-precipitation process occurs, perhaps on the scale of a single clay particle. These experiments highlight the importance of pH as a control over illitization and show that organic anions can buffer fluid composition into the optimum aK+/aH+ condition for illitization. These findings are highly significant for the smectite-to-illite reaction occurring in organic bearing sediments where organic acid anions are generated during kerogen maturation.
Micropore formation in heated synthetic Al-goethites from a ferrous system
Authors: Ruan H. D. , Gilkes R. J.
Published: December 2006

Nitrogen adsorption and desorption isotherms were obtained for microcrystalline, platy crystals of synthetic Al-substituted goethites synthesized from the ferrous system and heated to 260°C. Specific surface area, cumulative pore area and frequency of mesopore wall-separations of 2–15 nm in size increased as Al substitution increased. Nanometre-size micropores developed at heating temperatures between 200 and 240°C and decreased during the growth of hematite crystals between 240 and 260°C. Aluminium substitution had little effect on micropore development and a moderate effect on mesopore development. The increases in micropore volume and specific surface area due to heating are much smaller than is reported in the literature for large, lath-like crystals of goethite that develop abundant slit-shaped micropores.
Effects of hydrothermal activity on clay mineral diagenesis in Miocene shales and sandstones from the Ulleung (Tsushima) back-arc basin, East Sea (Sea of Japan), Korea
Authors: Hillier S. , Son B. K. , Velde B.
Published: December 2006

Clay mineral assemblages in both shales and sandstones of Miocene age have been studied in a well from the Ulleung Basin, a back-arc basin in the East Sea. Samples were examined from burial depths of ~800 to 3000 m. At the shallowest depths the shales contain assemblages dominated by R0 mixed-layer illite-smectite (I-S) together with illite, kaolinite and minor chlorite. The sandstones also contain I-S, but are dominated by large amounts of authigenic kaolinite. In both shales and sandstones I-S becomes R1 ordered at ~ 1000 m depth and at 2000 m depth, and deeper, I-S expandabilities are <20%. At ~ 2400 m depth, kaolinite in the sandstones is replaced by abundant Li-tosudite, indicating that clay mineral diagenesis has been affected by a hydrothermal episode. Furthermore, organic maturity data indicate that much of the succession has experienced considerably higher temperatures in the past. Vitrinite reflectance data are best modelled by a short lived (0.1–0.01 Ma) heating event in the Pliocene. This suggests that the shallow depths over which the smectite to illite reaction is completed and the extensive kaolinitization of the Miocene sandstones may also be related to the hydrothermal event.
Green clays from the Lower Oligocene of Aardebrug, Belgium: a re-evaluation
Authors: Huggett J.M. , Laenen B. , Vandenberghe N.
Published: December 2006

Porrenga (1968) described the green clays from the Lower Oligocene of Aardebrug, east of Leuven (Louvain) in Belgium as glauconitic illite, a mineral intermediate in chemistry between glauconite and illite, and presumed this clay to be neoformed, though the mode of origin is not discussed. Notably, most of the section from which Porrenga obtained his sample of 'glauconitic illite' is nonmarine. Non-marine glauconites are rare in the literature and there is no standard terminology. Parry and Reeves (1966) reported green pellets of 10 Å clay from recent sediments at Lake Mound, Texas, but with no detrital green clay as source and an authigenic origin is assumed. Green clays described as Fe-rich mica occur in lacustrine environments in the Oligocene of Cantal (Jung, 1954), and the Massif Central (Gabis, 1963) in France. These deposits are derived from altered crystalline basement.
Separation of chlorophenols using columns of hydroxyaluminium interlayered clays
Authors: Albanis T.A. , Danis T.G. , Pomonis P.J.
Published: December 2006

Clay minerals play an important role in the retention, transport and chemistry of organic micropollutants in soils. There has been considerable recent interest in modelling and designing modified clays as adsorbents and catalysts for the removal of contaminants from waste waters (McBride et al., 1977; Mortland et al., 1986; Boyd et al., 1988). Organo-clays have been used as chromatographic stationary phases over the past three decades. White (1957) and Barrer & Hampton (1957) used alkylammonium montmorillonites as stationary phases and determined the selective retention of aromatic hydrocarbons relative to paraffins, naphthalenes and xylenes. Until now only organo-clays have received attention as chromatographic stationary phases (McAtee & Robbins, 1980) while their pillared variants have been totally ignored.
A method to study the effect of chemical dissolution on the morphology of soil clay
Authors: Hagiwara M.
Published: December 2006

Soil clays contain a relatively large amount of disordered inorganic material. Chemical dissolution has been used for the removal of this material (Jackson, 1956; Hashimoto & Jackson, 1960; Follett et al, 1965 a,b; Wada & Greenland, 1970). On the other hand, Farmer et al. (1977) claimed that dissolution of allophane and imogolite with hot 5% Na2CO3 for periods of 2-100 h led to new phases which could be distinguished from the starting material by infrared spectroscopy. It is clear, therefore, that chemical dissolution can alter soil clays. This note suggests an electron microscopy specimen preparation technique to study the morphological changes. Collodion films containing densely arranged minute hollows are used for specimen supports.
Palygorskite occurrences in the Portuguese sector of the Tagus basin: a preliminary report
Authors: Dias I. , Gonzalez I. , Prates S. , Galan E.
Published: December 2006

Palygorskite and sepiolite occurrences and deposits are frequent in the Iberian Peninsula, mainly in the Tagus basin, in central Spain and Portugal (Galán & Castillo, 1984).

In Portugal, the first palygorskite occurrence was reported by Carvalho (1964) in the region of Ponte do Sor, Tagus basin, in Paleogene sediments. Later, Carvalho (1968) reported palygorskite occurrences in coarse detrital sediments that were occasionally carbonatic or hardened by silicification, and built up the Cenozoic base for the Tagus and Sado basins. Carvalho referred to such formations as the 'Attapulgite complex'. Overlying this attapulgite complex is the 'Montmorillonite complex', probably of Miocene age.
Clay mineral transformations in podzolized tills in central Finland
Authors: Righi D. , Räisänen M. L. , Gillot F.
Published: December 2006

Transformations of clay minerals were studied in a sequence of podzols (Entic Cryorthods) of increasing age (5500-10000 years BP) developed from till materials in central Finland. The age of the soils was estimated according to altitude above the present sea level, with reference to the age of ancient shorelines and the rate of land uplift. Clay minerals in fine (<0.1 µm), coarse (0.1-2 µm) clay and fine silt (2-5 µm) fractions were studied by X-ray diffraction. The layer charge of expandable minerals was estimated on the basis of their re-expansion with ethylene glycol following K-saturation and heating to 110°C Pedogenic transformations of clay minerals occur essentially in the E horizons of the podzols. Smectites and illite-smectite mixed-layers are the dominant clay minerals in the E horizons of soils older than 6500 years. The number of mixed-layers decreases with evolution of the soil, leaving a nearly pure smectite phase in the oldest soil (10000 years). The smectites are dioctahedral with a tetrahedral charge. Groups of low-charge and highcharge interlayers are both present in the samples, but low-charge smectite layers were found only in the two older soils (9500-10000 years). This suggests alteration with time of the high-charge smectites.
Note on the construction of models to illustrate theories of crystal structure
Authors: Bowman H. L.
Published: December 2006

There are probably few subjects for the study of which models are more indispensable than the theories of crystal structure ; but the provision of any considerable series of such models is costly, and they require, moreover, a large amount of space for storage. Some interchangeable models, which the author has lately had constructed to illustrate the space-lattices and the regular point-systems of Sohncke, and which may be fitted up and taken to pieces as required, have been found so convenient, both for lectures and for private study, that a short description of them may be found useful, although they differ only in details of construction from those suggested by Sohncke.
The natural history of Kaolinite
Authors: Butler Francis H.
Published: December 2006

In the south-west coal-field of east Glamorganshire—especially in the Lower Coal Measures–Mr. A. Tait, of Caerphilly, observed last year a white, soft, and pulverulent substance, saponaceous to the touch. A specimen sent to me, examined first and identified by Mr. T. Crook, was found to consist of a congeries of well-defined crystals of kaolinite. The crystals are chiefly basal flakes, hexagonal in outline, and 0.02 to 0.037 mm. in length. Most of them show elongation in one direction, and unequal extension of the thin lamellae composing them.
On the relation between Rathite, Rathite a, and Wiltshireite
Authors: Solly R. H.
Published: December 2006

At the Society's Anniversary Meeting of November, 1908, I exhibited and gave an account of an unnamed crystal from the dolomite of the Leugenbach quarry in the Binnenthal, Switzerland. In the notice of this meeting, as given in ‘Nature’ of December 10, 1908 (vol. lxix, p. 142), this mineral, which could not be identified with any of the sulpharsenites of lead previously described, is referred to as follows :— ‘One of these [black minerals with metallic lustre] is oblique with β = 81° 11′, (100),(101)= 40° 7′, (010),(111) = 5° 26′; it has a perfect cleavage (100), and, like liveingite, exhibits no oblique striations on the planes in the zone [100,001].’ Owing to lack of material, the chemical composition and specific gravity of this apparently new mineral could not be determined.
Notes on the occurrence of Dundasite in Derbyshire and Co. Galway
Authors: Russell Arthur
Published: December 2006

An occurrence of the rare mineral dundasite (hydrous carbonate of lead and aluminium) at the Welsh Foxdale mine, Trefriw, Carnarvonshire, was described by Dr. G. T. Prior in 1906. Since then the mineral has been found by the writer at two additional localities in the United Kingdom. Certain specimens collected in 1910 at the well-known Mill Close mine, Wensley, Derbyshire, show a mineral which examination has proved to be dundasite. It occurs here as minute white or yellow spheres, not exceeding ¾ mm. in diameter, the exterior smooth and waxy, the interior radiating and silky.
The graphical determination of angles and indices in zones
Authors: Smith G. F. Herbert
Published: December 2006

Nine years ago (in 1904) I described a diagram—the moriogram, as I called it—which served for the graphical determin.stion of angles and indices in the case of zones in which the principal poles included a right angle. It was, therefore, restricted in its application to zones in the cubic, tetragonal, orthorhombic, hexagonal, and rhombohedral systems, and to zones in the monoclinic system passing through the pole of symmetry. Although the moriogram may be used with sufficient accuracy for practical purposes in the case of many substances with triclinic symmetry, in which the angles between the principal poles differ little from right angles, there necessarily remain many instances in which it cannot be applied with any approximation to accuracy.
On the remarkable similarity in chemical and mineral composition of chondritic meteoric stones
Authors: Prior G. T.
Published: December 2006

The observation of the striking similarity both in chemical and mineral composition of the Baroti, Wittekrantz, and St. Michel meteorites (see the preceding paper) suggested the idea of testing how far such a close relationship applied to other cbondritic meteoric stones.

The practical identity in chemical composition of different meteoric stones has been often pointed out. For example, A. E. Nordenskiöld showed in the case of the stones of Erxleben, Lixna, Blansko, Ohaba, Pillistfer, Dundrum, Hessle, Orvinio, and Stäilldalen that the percentage chemical compositions differed very slightly if the proportions of the metals, silicon, &c., were considered instead of the oxides.
Barkevikite from Lugar, Ayrshire
Authors: Scott Alexander
Published: December 2006

In recent years a number of alkali-rich rocks have been described, containing barkevikite or 'barkevikitic hornblende.' So far as I am aware, however, no detailed examination has been made of the mineral since Brögger's work on the original material from Barkevik in Norway, with the exception of the investigation by Michel Levy and Laeroix. Hence, when a rock was found amongst the Permo-Carboniferous rocks of Ayrshire, with comparatively large crystals of barkevikite, it was decided to examine it in some detail.
The determination of the maximum extinction-angle, optic axial angle, and birefringence in twinned crystals of monoclinic pyroxenes in thin section by the Becke method
Authors: Collingridge Harvey
Published: December 2006

In nearly every thin section of a rock containing monoelinic pyroxenes it will be found that one or more crystals twinned on the orthopinacoid (100) are included. In such crystals the twin-plane is marked very clearly by the difference of relative retardation and extinction, and also by the interference-bands if the twin-plane is inclined to the plane of section. For the purposes of the complete optical determination, it is essential for the proposed method that one half of the twin should exhibit the emergence of an optic axis suitable for the determination of the optic axial angle by the Becke method.
On crystals of Albite from Alp Rischuna, and pericline twins from La Fibbia, Switzerland
Authors: Lewis W. J.
Published: December 2006

The Cambridge Museum recently acquired a number of albite specimens from Alp Rischuna, near Yals Platz in Switzerland. Many of the crystals had good faces, so that measurement of the angles seemed likely to give trustworthy crystal-elements.
The dispersion phenomena of Albite from Alp Rischuna, Switzerland
Authors: Kôzu S.
Published: December 2006

The refractive indices of this mineral for different wave-lengths were determined by the Abbé-Pulfrich total-reflectometer. The dispersion of the glass hemisphere of the instrument was determined by the aid of a highly polished glass prism, the dispersion of the latter being found by the method of minimum deviation. In order to obtain light of definite wave-length Hilger's wave-length spectrometer was used with a Nernst lamp or an electric arc as the source of illumination.
On Childrenite from Crinnis mine, Cornwall, and Eosphorite from Poland, Maine
Authors: Drugman Julien
Published: December 2006

Up to the present time only one of the several ehildrenite occurrences known has been examined both chemically and crystallographieally. This is the well-known occurrence at the George and Charlotte mine near Tavistock, from which nearly all the specimens seen in collections were obtained. The crystals often attain a dimension of 1 cm., so that material for analysis can be easily obtained free from gangue. Crystals from this locality were analysed by Rammelsberg, Church, and Penfield, and it is on the results obtained by the last-named that the comparatively simple formula for this mineral is based.
On the genetic relationship and clasaification of Meteorites
Authors: Prior G. T.
Published: December 2006

In a previous paper attention was drawn to the close similarity in mineral and chemical composition of chondritic meteoric stones. In the case of about forty chondrites it was shown that, apart from variations in the amount of nickel-iron, not only are the constituent minerals present in very similar amounts, but their chemical compositions vary to no very great extent. In that paper sufficient importance was not attached to the variations in the amount of nickel-iron.
A method of determining the angular direction represented by a point in the directions-image of an object under the microscope
Authors: William Evans John
Published: December 2006

The determination of the direction in which the light illuminating a point in a directions-image (the so-called image in convergent light) was travelling when it reached the objective has hitherto been carried out by first measuring the position of the point in the image and thence calculating the angular direction it represents. It is usually assumed that the distance of a point in the image from the centre of the field is in proportion to the sine of the angle between the path of the light that illuminates the point and the axis of the microscope.
The basaltic rocks of the Arctic region
Authors: Holmes Arthur
Published: December 2006

The widespread basaltic rocks of tile Brito-krctic province, like those of the Deccan and Columbia basalt plateaux, do not seem to have received from petrologists the attention they deserve. Descriptions of particular localities and their rocks are not lacking, and the British region in particular has become classic through the investigations of Judd, Sir A. Geikie, and Dr. Harker, but hitherto no attempt has been made to survey the province as a whole, except in the most general way.
On changing the plane of a gnomonic or stereographic projection
Authors: Hilton Harold
Published: December 2006

Consider the poles of the faces of a crystal and the zones (great circles) which join them. Suppose we have given their gnomonic projection on to a certain tangent-plane to the fundamental sphere on which these poles and zones lie. We can find the gnomonic projection on any other plane by aid of the gnomonic net, as explained in this Magazine (1904, vol. xiv, p. 19); and similarly for the stereographic or orthographic projection.
Mineralogical characters of Turite ( = turgite) and some other iron-ores from Nova Scotia
Authors: Spencer L. J.
Published: December 2006

The material examined forms part of the late Dr. Henry S. Peele's collection, which shortly before his death he decided to present to the British Museum. Dr. Poole was at one time Government Inspector of Mines in Nova Scotia, and his collection is rich in Nova Section ores and minerals from many well-defined localities.
On the occurrence of Phenacite and Scheelite at Wheal Cock, St. Just, Cornwall
Authors: Russell Arthur
Published: December 2006

James Sowerby in his ‘British Mineralogy’ describes and figures sider the head of ‘Argilla electrica’ or ‘White Tourmaline’ a mineral which was undoubtedly phenacite. The specimen was sent to Sowerb,y by a Mr. Herbert in 1804, and was said to have been found in a mine in St. Just, Cornwall. According to Sowerby's description and from the eoloured plate which he gives of the specimen, the mineral occurred as long-prismatlc, colourless crystals , some of which were doubly terminated and lying upon and partly penetrated by mass of prismatic quartz crystals. The crystals were ‘so divided by cracks and flaws in general as to appear of an opaque whiteness in parts’.
A new model rotating-stage petrological microscope
Authors: Alfred Richardson W.
Published: December 2006

Present industrial conditions have tbrccd the engineering trades of the country to adopt methods of mass production, in order to cope with increases in the cost of raw materials and labour. Specialized trades such as the manufacture of scientific instruments are unable to develop quite on these lines, partly because of the limited demands for their goods, and partly because each job is largely an individual one. In the microscope trade much has been done by systematic shop organization, and at the same time an approach is made to mass production by considerably reducing the number of models made, and standardizing the remainder. Naturally the large models for special work have been most affected.
On the absence of cobalt in Cornetite from Katanga, Belgian Congo
Authors: Schoep Alfred
Published: December 2006

It has been proved by the work ot Messrs. A. Hutchinson and A. M. Macgregor, recently published in this Magazine (1921, vol. 19, pp. 225-232) under the title 'Oil cornetite from Bwana Mkubwa, Northern Rhodesia', that the only difference—if any—between the Rhodesian mineral and the original cornetite from Katanga consists in the presence of cobalt as determined by Professor G. Cesàro in the crystals from the Étoile du Congo mine. It may be of interest to give here the results of my researches on the chemical composition of the cornetite from the Étoile du Congo mine in Katanga.
The meteoric stone which fell at Ashdon, Essex, on March 9, 1923
Authors: Prior G. T.
Published: December 2006

The stone was seen to fall, at about 1 p.m. on March 9, 1923, by a thatcher named Frederick Pratt who was working at the time in a corner os a wheat-field on Ashdon Hall farm, Ashdon, near Saffron Walden, Essex. He heard a strange ‘sissing’ sound, and, supposing an aeroplane was overhead, looked up and a second or two after saw what he thought was a projectile fall about thirty yards from him into the wheat-field a few feet from the farm-road, causing the earth to ‘fly up like water’. Three days later, in company with another worker on Ashdon tIall farm named Curven, he dug up the stone from a depth of about two feet.
Crystallographic data for some organic compounds
Authors: Greenwood Gilbert
Published: December 2006

The isomorphous relationships for organic compounds are not so simple as they sometimes are for inorganic. Very often a series of chemically similar orgallic substances does not show any apparent trace of crystallographic similarity. It appears that the introduction of further groups into the molecule may cause the crystal-system to change in a manner which cannot be predicted. Thus, glyoxalinc-4(or 5)- sulphonic acid is tetragonal, whilst 4(or 5)-bromoglyoxaline-5(or 4)- sulphonic acid is monoclinic; the introduction of a methyl group into the 2 position gives rise to an orthorhombic crystal, whilst the introduction of the same group into the 1 position leaves the crystal-system unchanged. In some cases it has been found that evell though the crystal-system is changed, there still remains a very close similarity between corresponding angles in the different substances.
The structure of aragonite
Authors: Tomkeieff Serge I.
Published: December 2006

We are unable to observe crystalline structure directly, and can only infer it by observation of the physical and chemical properties possessed by a crystal. It is quite reasonable to suppose that every vectorial property possessed by a crystal is dependent upon its leptonic structure. The X-ray method, which has produced such a revolutionary change in our Knowledge of crystal-structure, is not sufficient in some cases for the determination of leptonic structure. The X-ray spectral analysis gives only the spacings between the atomic planes of a crystal. The application of the method of intensities, which was so successful in the case of simple cubic crystals, may not be so in the case of crystals of a Inore complex chemical composition and of a lower symmetry. It is thus desirable to combine several methods and so approach the problem from different directions.
Chlorophaeite in the dolerites (tholeiites) of Dalmahoy and Kaimes Hills, Edinburgh
Authors: Campbell Robert , Lunn James W.
Published: December 2006

The name chlorophaeite was given by John Macceulloch in 1819 to a mineral exhibiting striking colour change on exposure which he found at Craig nan Stàrdean (=Sgùrr Mòr) in the island of Rum. Sixty years later Professor Heddle visited the type locality and redescribed the mineral, giving for the first time chemical analyses. He also noted an occurrence of the mineral in Canna. In 1908 A. Harker showed that the rock which contained the chlorophaeite belongs to the mugearites.

Records of chlorophaeite arc not always trustworthy since the term has been used somewhat loosely. Professor Heddle (loc. cit., p. 88) confirmed the occurrence at the Giant's Causeway, Co. Antrim, first recorded by Greg and Lettsom in their Manual of Mineralogy.
The construction and use of an X-ray goniometer. Crystal-structure of glyoxaline compounds (With Plate I.)
Authors: Greenwood Gilbert
Published: December 2006

In ordinary circumstances crystal-angles are measured by means of light reflected from the crystal-faces. In the partial or complete absence of faces the determination of axial ratios and angles may be impossible. In a recent investigation of certain derivatives of glyoxaline, an example of this was found. It was, in fact, the substance glyoxaline itself, which always occurred as long prisms having four faces in the prism-zone; the ends of the prisms were jagged and rough, and no siglls of optically reflecting-planes could be found on these ends. In such a case, X-ray methods of investigation are now available, and the problem in question is the determination of the dimensions of the unit-cell, not the complete X-ray inveatigation of the structure.
The structure of baddeleyite and of prepared zirconia
Authors: Yardley Kathleen
Published: December 2006

The crystal used in the first part of this investigation, an untwinned specimen from Ceylon in the British Museum collection, was measured goniometrically and described in detail by Dr. G. F. Herbert Smith, who gave as its crystallographic constants :

Density (p) 5.82 (grs./c.c.). Monoelinic prismatic,

a:b:c = 0.9905 : 1:0.5110, β = 80° 32'.

Owing to the comparatively largc size of the crystal and its high absorptive power it was unsuited either to the 'rotating crystal' or Laue photographic methods of X-ray examination, Reflections from the faces were observed on the Bragg ionization spectrometer and spacings measured with an accuracy of about 2 per cent.
On the distribution of purple zircon in British sedimentary rocks
Authors: Boswell P. G. H.
Published: December 2006

By the publication of his paper on 'The source of the purple zircons in the sedimentary rocks of Scotland', Dr. Wm. Mackie has done his fellow-workers on the petrology of British sedimentary rocks a signal service, He has proved that this distinctive purple (or sometimes rosecoloured) variety of zircon is relatively abundant in the Lewisian gneiss. The variety occurs usually as rounded or ovoid grains, but occasionally with crystalline form ; it is often finely polished, as if by wind, and is sometimes zoned, with a darker centre, or displays colour of varying intensity; it is often definitely, although but slightly, pleochroic, and usually possesses high bireffingence. These characteristics at once bring to mind grains of zircon frequently met with in sedimentary rocks and recorded by numerous other observers.
Corundum twins from Transvaal
Authors: Spencer L. J.
Published: December 2006

Lamellar twinning is of frequent occurrence in corundum, as evidenced by rulings on the surfaces and by the well-marked pseudo-cleavages (or partings) parallel to the faces of the primary rhombohedron and also parallel to the basal plane. Distinctly developed juxtaposition and interpenetration twins would, however, appear to be rare, for only a few isolated examples have hitherto been described.

There are two twin-laws for corundum crystals, the twin-plane being either r (101̄l) = (100) or c (0001) = (111). The former of these is the one considered in the present note.
Specific gravities of minerals: an index of some recent determinations
Authors: Spencer L. J.
Published: December 2006

As a first-aid in the identification of non-metallic minerals I have for many years made use of specific gravity, which is a character that can be easily and rapidly determined hy the use of heavy liquids. A small, clean fragment of the mineral to be tested is dropped into one or other of a series of tubes containing methylene iodide with various small known Crystals as indicators. Adding benzene from a dropping-bottle, the density of the liquid is quickly brought to that of the mineral. This preliminary determination of the specific gravity gives a useful clue as to the nature of the mineral—what it may or may not be ; and the same fragment can then be used for confirmatory optical and micro-chemical tests.
Notice of an occurrence of niccolite and ullmannite at the Settlingstones Mine, Fourstones, Northumberland; and of serpierite at Ross Island Mine, Killarney, Co. Kerry, Ireland
Authors: Russell Arthur
Published: December 2006

The old mine Settlingstones, situated three miles north of Haydon Bridge in the county of Northumberland, was originally worked as a lead mine, but, during the htst fifty years, as the vein has been explored farther west, it has attained far greater importance as the largest and most consistent producer of witherite in the British Isles. The Settlingstones main vein has a direction approximately north-east and southwest, and has been proved for a distance of nearly 1½ miles. The vein has varied in width from 3 feet up to 40 feet, the most productive witherite-bearing portion averaging 10 to 12 feet. The enclosing rocks are sandstones ('whetstones') and shales ('plate') of Carboniferous age, and dolerite (Whin-sil) which here attains a thickness of a little over 21 fathoms.
Potarite, a new mineral discovered by the late Sir John Harrison in British Guiana
Authors: Spencer L. J.
Published: December 2006

The untimely death of Sir John B. Harrison on February 8, 1926, just as he was returning home after over forty-six years' service in the West Indian colonies; unfortunately prevented the publication by him of a complete account of the interesting new mineral which, as a result of much patient chemical work, he had discovered in British Guiana. As he had corresponded with me on this matter since April, 1924, and further, as this is the same mineral that I had myself erroneously described as 'allopalladium', I feel it my duty to place on record the full facts so far as can now be ascertained.

I had suggested that the new mineral might be named after Sir John Harrison, but this he objected to ; and, in consultation with the Governor of British Guiana, he proposed the name potarite (letter of April 8, 1925), but he did not himself record this name in print.
The tholeiite dikes of the north of England
Authors: Holmes Arthur , Harwood H. F.
Published: December 2006

The suite of dikes that forms the subject of this paper is bounded on the south from Sleights Moor (south of Whitby) to Dalston (south of Carlisle) by the well-known series of dikes known collectively as the Cleveland-Cockfield-Armathwaite dike, and on the north by the nearly parallel and more continuous Acklington dike which stretchesfrom Bondicarr near Coquet Island across the southern margin of the Cheviots into Scotland.
An investigation into the piezo-electric effect of diamond
Authors: Wooster W. A.
Published: December 2006

Introduction—Opinion is divided as to the true crystal symmetry of diamond. Some authors, notably Fersman and Goldschmidt, who have investigated its morphological and etch characters, consider it is always hemihedral, whilst others, by the same methods, have obtained results which indicate holohedrism. Early work by A. Artom showed that it was seldom piezo-electric, but more frequently pyro-electric. Van der Veen also carried out avery thorough investigation and found no piezo- or pyro-electricity in his five diamonds. These were octahedral in shape, and not very suitable for this experiment.
On larnite (calcium orthosilicate, a new mineral) and its associated minerals from the limestone contact-zone of Scawt Hill, Co. Antrim
Authors: Tilley C. E.
Published: December 2006

The contact-zone of Chalk and Tertiary dolerite at Scawt Hill, near Larne, Co. Antrim, consists of an assemblage of comparatively rare minerals, including a mineral of the composition Ca2SiO4 not previously recognized as a naturally occurring compound. In the assemblages of the contact-zone the chief minerals, apart from calcite, are spurrite, calcium orthosilieate (larnite), melilite (gehlenite), merwinite, spinel, perovskite, and wollastonite. Outside this contact-zone, the chalk consists almost wholly of calcium carbonate ; nearer the contact it is recrystallized to a granular mosaic of calcite of coarse texture, while at the immediate contact the chalk is completely transformed into an aggregate of new-formed silicates in varying proportions. A hybrid zone between the dolerite and the exogenous contact-rock is composed Of a coarsely crystalline rock built up essentially of titanaugite, melilite (humboldtilite), nepheline, wollastonite, perovskite, and various zeolites. An account of the melilite of this hybrid zone has already been given.
A study of the calc-gneisses, scapolite-gneisses, and cordierite-garnet-sillimanite-rocks of Coimbatore, Madras Presidency; with comparison to other similar occurrences in India
Authors: Narayana Iyer L. A.
Published: December 2006

The Indian peninsula, though considered to be a very stable part the earth's crust and hence called the 'Indian Shield', shows in different parts evidence of formerly having sustained epicontinental basins, in which sedimentation occurred. These sediments are now found in detached prisms as crystalline gneisses and schists in different parts of India, e.g. in the Madras Presidency, Bihar and Orissa, Central Provinces, Central India, and Rajputana. They have been found overlying the ancient gneigses (Archaean), and belong to a division known in Indian geology as the Dharwar System.
Bismutotantalite, a new mineral, from Uganda
Authors: Wayland E. J. , Spencer L. J.
Published: December 2006

The discovery of tin-ore in Ankole (south-western Uganda) led to a great deal of prospecting on the part of qualified and unqualified, experienced and inexperienced, individuals, not only in the vicinity of the original discoveries, but also in many other parts of the Protectorate. One of the results of this activity was the finding, by a prospector, of a deposit of alleged coal at a spot rather less than 25 miles WNW. (approx.) of Kampala and about 35 miles NW. of Entebbe. With reference to this, the discoverer was told by the Geological Survey that his hoped-for fuel was in reality tourmaline, but inasmuch as it was associated with a pinkish-buff mica characteristic of the stanniferous pegmatites of Ankole, further search might disclose the presence of tinstone.
A new meteoric iron from Piedade do Bagre, Minas Geraes, Brazil
Authors: Spencer L. J.
Published: December 2006

A mass of iron weighing 130 lb., stated to have been found in 1922 near the village of Piedade do Bagre in Minas Geraes, Brazil, and believed to be meteoric, was submitted by Mr. N. Medawar in January 1929 to the Mineral Department of the British Museum for examination. The following description of the mass fully confirms the supposition of its meteoric origin. Unfortunately, only scanty details are available of the circumstances of the finding of the mass. All the information that Mr. Medawar was able to supply is given in the following short note written by Mr. R. J. Bohrer, with a rough sketch-map of the locality.
The distinction of analcime from leucite in rocks by X-ray methods
Authors: Bannister F. A.
Published: December 2006

Since W. Lindgren first detected the presence of microphenocrysts of analcime in basalt, many observers have recorded this mineral as a constituent of igneous rocks, but there is some difficulty in distinguishing between analcime and glass and between analcime and leucite in thin rock-sections. For instance, H. Rosenbusch identified the interstitial colourless isotropic material in monchiquites as glass, whereas L. V. Pirsson showed it to be analcime. H.S. Washington showed that basalts from Sardinia, previously thought to be leueitic, contain phenocrysts of analcime. A. Lacroix also found, in his study of north African basaltic lavas, that in many cases so-called leucite-lavas actually contain analcime and not leucite.
The Dhoon (Isle of Man) granite : a study in contamination
Authors: Nockolds S. R.
Published: December 2006

The Dhoon granite is contained in sheets 8 SW. and 8 SE. of the 6-inch Ordnance Survey Maps of the Isle of Man. It is a bosslike intrusion of irregular outcrop (fig. 1), enclosing an area about one and one-third miles long in an east-west direction, and half a mile wide in a north-south direction. It has been intruded into rocks which form part of that division of the Manx slates known as the Lonan Flags, and has metamorphosed these to a certain extent.
Notes on brown hornblende and biotite from Shabō-zan, of the Dalton volcanoes, Taiwan, Japan
Authors: Ichimura Takeshi
Published: December 2006

The Dalton volcanoes include all the volcanic groups which rise up at the north-western end of Taiwan (Formosa). They are old extinct volcanoes underlain by highly disturbed Tertiary sediments. Among them Shichisei-zan is the highest and the most prominent, rising up to 1108.7 metres above sea-level. It is mostly made up of hornb]ende-andesite, hypersthene-hornblende-andesite, and agglomerates. On the western slope of this partly dissected volcano there is a very characteristic cone called Shabō-zan. Its elevation is 643 metres above sea-level, and it is mostly made up of hypersthenehornblende- andesite poured out through the thick accumulation of agglomerates. The andesite here has usually a grey colour, but often passes into a light reddish-brown variety, being sometimes associated with a noritic segregation mass. It is noteworthy that some of the andesites abundantly contain brown hornblende. This mineral also frequently appears, together with brown biotite, in the segregation mass.
Almandine from Botallack, Cornwall
Authors: Alderman A. R.
Published: December 2006

Well-Crystallized icositetrahedral garnets from Botallack, Cornwall, are preserved in most British mineral collections, but they have previously not been systematically examined. The original specimens were discovered in 1821 by a St. Just miner who dealt in minerals, and the occurrence is first referred to by Carne in his paper 'On the mineral productions and the geology of the parish of St. Just' as follows : 'About six months ago, a mass of beautiful garnets, of a deep red colour, was found imbedded in the rock, not far from low water mark at the foot of Chycornish Carn, about a quarter of a mile south of Botallack. Some of the crystals were larger than hazel-nuts, and most of them were twenty-four sided. Some specimens of a very superior order were procured, each having from one to two hundred crystals on its face.'
On the occurrence of chondrodite in the Glenelg limestone of Inverness-shire
Authors: Read H. H. , Double I. S.
Published: December 2006

Introduction.-There are many old records of the occurrence of chondrodite in the British Isles. Greg and Lettsom mentioned Co. Donegal in Ireland and near Loch Ness in Scotland. J.H. Collins gave Wheal Druid, Redruth, and also Scotland and Ireland. The mineral is included in a list of those associated with the kyanite of Glen Urquhart, Loch Ness, Inverness-shire, given by T. Wallace. Though reference to the Loch Ness locality is made by Dana in the 6th edition of the 'System' (1892, p. 540), the existence of chondrodite at Glen Urquhart, the only likely locality near Loch Ness, had been queried by M. F. Heddle so early as 1879. Heddle failed to find chondrodite at this locality; he gave the name xantholite to a yellowish serpentinous substance that he suggested had been hitherto mistaken for chondrodite.
The influence of chemical factors on the crystallization of hornblende in igneous rocks
Authors: Kennedy W. Q.
Published: December 2006

It is now more than sixty years since Tschermak first published his classical paper on the relationship between the pyroxenes and amphiboles, but, in spite of our greatly increased knowledge of these important rock-forming minerals, many of the problems concerning their constitution and genesis remain unsolved. In particular, the nature of the conditions which determine whether a pyroxene or an amphibole will separate from a crystallizing magma are imperfectly understood, although the point is one of very considerable petrological significance. Much fuller information is necessary, particularly with regard to the relationship between the composition of the ferromagnesian minerals and the rocks in which they occur. The present paper merely represents a preliminary attempt to correlate the available chemical evidence and to determine what other possible factors might influence the character of the ferromagnesian crystallization.
Fictitious occurrences of iron silicide (ferrosilicon)
Authors: Spencer L. J.
Published: December 2006

Ferrosilicon is occasionally found under circumstances that suggest that it is a natural mineral. Twice during the past quarter of a century it has been described as a new mineral, and the error was detected only after preliminary accounts had been published. It has also at times been thought to be meteoric. A supposed meteoric iron from North Carolina was described by C. U. Shepard in 1859 as composed of a material to which he gave the name 'ferrosilicine'.

The following notes collected during several years contain nothing new. They are merely brought together to serve as a warning against an error that may recur.

On several occasions between 1924 and 1929 Mr. H. N. G. Cobbe, a consulting mining engineer, sent to me for identification rounded pieces of a metallic substance that had been picked out from the concentrates of the gold dredgers on rivers and creeks in British Guiana.
Baryte crystals from the Manvers Main colliery, Wath-upon-Dearne, near Rotherham, Yorkshire
Authors: Russell Arthur
Published: December 2006

Early in the summer of 1930 there was exposed in the Parkgate Seam, No. 3 Pit of the Manvers Main colliery, Wath-upon- Dearne, near Rotherham, Yorkshire, a large cavity lined with exceedingly beautiful crystals of baryte ; this being the first occurrence of the kind recorded in the south Yorkshire coalfield. The cavity was quickly more or less completely wrecked by the miners, when fortunately my friend, Mr. C. P. Finn, the Company's chemist, had his attention drawn to the matter, and as a result some brief notes on the occurrence, accompanied by a photograph of a specimen, were published by him. Thanks to the efforts of Mr. Finn, and as the result of visits to the colliery, I was able to obtain some very fine and interesting specimens of the mineral.