bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical conductivity of a montmorillonite-organic complex
Authors: Kato C. , Kuroda K. , Hasegawa K. 
Published: December 2006

AbstractVolume resistivities of various homoionic montmorillonite films and their polyacrylonitrile (PAN) complexes were determined with a high-resistance meter. It was found that: (i) electrical conductivities of the homoionic montmorillonite films decreased in the order: Li- > Na- > K- > Mg- > Ca- > Sr- > Ba-montmorillonite, (ii) conductivities of the PAN-complex films varied with the amount of polymer present in the interlaminar space, and (iii) heating the PAN-complex films for 12 h at 150°C generally resulted in an increase in conductivity due to carbonization of the polymer.
An illite/montmorillonite interlayer mineral in porphyritic rock of ‘Alpe Di Siusi’ (Bz-Italy): The chemistry of I/M interlayer minerals
Authors: Alietti A. , Brigatti M. F. , Poppi L. 
Published: December 2006

AbstractAn Illite/Montmorillonite mineral found in a porphyritic rock of Alpe di Siusi has an I/M ratio of 80:20. Introducing proper chemical parameters in a Q-Mode program of sixty-six Illites and Illite/Montmorillonite from the literature suggests the possibility of distinguishing Illites from Illite/Montmorillonite.
Influence des substances humiques sur les proprietes d'hydration des argiles—V.—Deshydratation des acides humiques
Authors: Chassin P. , Le Berre Brigitte 
Published: December 2006

RésuméDans les andosols, les horizons de surface et les horizons profonds sont caractérisés par des propriétés d'hydratation bien distinctes. Pour expliquer cette différence, nous avons supposé que la matière organique des horizons superficiels avait subi des dessiccations qui induisent des transformations moléculaires.Dans cette communication, nous montrons que la dessiccation d'une suspension d'humates calciques n'est pas un phénomène simple mais qu'elle se fait en trois étapes successives qui correspondraient à différents états physico-chimiques du couple matière organique-eau (agrégats moléculaires et eau libre, associations d'agrégats moléculaires avec eau capillaire et eau d'hydratation). On met également en évidence que ces trois étapes se distinguent d'autant moins que l'indice de polymolécularité est grand.
Activation of a sepiolite with dilute solutions of HNO3and subsequent heat treatments: III. Development of porosity
Authors: Rodríguez-Reinoso F. , Ramírez-Sáenz A. , López-González J. De D. , Valenzuela-Calahorro C. , Zurita-Herrera L. 
Published: December 2006

AbstractPorosity development in a sepiolite from Toledo, Spain, has been studied as a function of acid (0·25, 0·50, 0·75 and 1·0mHNO3) and subsequent heat treatments (110–400°C). Adsorption isotherms of N2at 77 K have been analysed byf-plot,t-plot,αs-plot and the Cranston & Inkley methods. Results are compared with those obtained on products heated without previous acid activation. Experimental conditions favouring porosity development are discussed.
Interlayer complexes of lanthanide-montmorillonites with amines
Authors: Bruque S. , Moreno-Real L. , Mozas T. , Rodriguez-Garcia A. 
Published: December 2006

AbstractSorption interlayer complexes of n-butylamine, sec-butylamine, iso-butylamine and diethylamine with homoionic Ln-montmorillonites (Ln = La, Sm, Gd, Er, Y) have been prepared. Compositions of the complexes are of the type: [Ln(butylamine)4]3+ and [Ln-(diethylamine)2]3+. The disposition of amine molecules surrounding the ion, the interaction between the amine group and the Ln3+ ion, and the strength of the ion-dipole bond have been studied by X-ray diffraction, IR spectroscopy and differential thermal analysis.
Water sorption on Ca-saturated clays: I. Multilayer sorption and microporosity in some illites
Authors: Branson Kathy , Newman A. C. D. 
Published: December 2006

AbstractMeasurements of water desorption and sorption on four Ca-saturated illitic clays show that the shapes of the isotherms are very similar to those for other oxide surfaces, indicating that the formation of water multilayers is quantitatively similar. This enables graphs of multilayer thickness against mass sorbed to be drawn and used to assess microporosity. Hysteresis occurs and this is attributed to loss of external surface as drying brings platy particles in close face-to-face contact. Mixed-layer mica-smectites, however, exhibit no microporosity by this test and behave as if all surfaces are freely accessible to multilayer formation. The reason for this is not at present understood.
On the occurrence of Bertrandite at the Cheesewring Quarry, near Liskeard, Cornwall
Authors: Bowman H. L. 
Published: December 2006

In the year 1904, two specimens were sent to me by Mr. F. H. Batler for determination, which showed small, colourless, rhombie or oblong tabular crystals on granite. The crystals proved on examination to be the beryllium silicate bertrandite, which forms a new addition to the list Of British mineral species.This mineral was first described by E. Bertrand in 1880 from the quarry of Petit Port, near Nantes, and it has since been found at other places in the same neighbourhood as well as in the old tin-workings at La Villeder in Morbihan, and near Alençon and Limoges, though always in very small quantity. Outside France it has been found only in the neighbourhood of Pisek in Bohemia ; and, in tile United States, at Stoneham and elsewhere in Maine, Amelia Court House in Virginia, and on Mt. Antero in Colorado.
Note on Calcite from the Chalk at Corfe Castle, Dorset
Authors: Bowman H. L. 
Published: December 2006

Some specimens of calcite which I obtained recently from a chalkpit at Corfe Castle in Dorsetshire appear worthy of description on account of their somewhat unusual habit and of the rarity of wellcrystallized minerals in the Chalk.The pit is situated in the Upper Chalk, not far from the great overthrust fault which traverses the Isle of Purbeck from west to east along the boundary of the Chalk and the overlying Tertiary beds. The Chalk is here steeply inclined, with a northerly dip, and is much indurated, being sufficiently hard to be worked for road-metal.
The possible axes of crystal-symmetry
Authors: Evans John William 
Published: December 2006

The following is a simple general proof that, on the hypothesis that crystals have a homogeneous cellular structure, the only possible axes of symmetry are those with cyclic numbers 2, 3, 4, or 6.According to this hypothesis, every crystal is entirely made up of minute space-partitions or ceils, which (apart from those of purely surface layers) have all the same form, size, internal configuration, orientation, and external relations. Accordingly, every point in one cell has an equivalent point exactly corresponding to it in every other cell.
An X-ray examination of substituted edingtonites
Authors: Taylor W. H. 
Published: December 2006

The rare barium zeolite edingtonite has been examined in the course of the systematic investigation of the zeolites now being made at the British Museum, and several substitution derivatives have been prepared. The structure of natural edingtonite has also been completely determined by X-ray methods, and in the present paper an account is given of an attempt to discover the exact positions occupied in the substituted edingtonites by the potassium and thallium ions which replace the barium ions of ordinary edingtonite.Base-exchange products obtained from some other zeolites have already been examined in detail by X-ray methods. In silveranalcime and silver-natrolite the intensities of X-ray reflections are explained satisfactorily on the assumption that each silver ion occupies the exact position previously occupied by the sodium ion which it replaces.
The Morven meteorite, an aerolite from South Canterbury, New Zealand
Authors: Hutton C. O. 
Published: December 2006

The meteoric stone to be described was found in 1925 by Mr. William Stewart while ploughing on his farm four-and-a-half miles south of the Morven railway station (44° 49' S., 171° 8' E.) in South Canterbury, about one hundred miles north-east of Dunedin, New Zealand. It must have weighed originally about 7100 grams, but when presented to the Otago University Museum it weighed 14lb. 14oz. (6753 grams), the remainder having been broken off by the finder. There is no local record of the fall, and the nature of the weathered crust suggests that it may have been in the soil for a long time.The stone (fig: 1) is roughly pyramidal, measuring approximately 22.5 x 17.5 x 15.0 cm. It was covered with a thin, soft ochreous crust occasionally as much as 2-3 mm. thick.
The Tauq, ‘Iraq, meteorite
Authors: Macfadyen W. A. , Claringbull G. F. 
Published: December 2006

In December 1933 Major W. A. Pover, who was then ‘Iraq Public Works Department Executive Engineer of the Mosul and Kirkuk Liwas, showed the writer a portion of a meteoritic stone. This had been in his office doing duty as a paper-weight since it was brought to him by two of his men shortly after its fall.At that time Major Pover was in camp, supervising the erection of the permanent steel road bridge that spans the river valley some five kilometres upstream of Tauq village. His men told him that the meteorite fell in the middle of the night; it was likened by those who saw it to the moon falling, and people were awakened by the jolt of its fall. When the morning came, some of his men went out to seek it, and they in fact found it. They described it as about two and a half feet in diameter, and they broke it up with a sledge hammer, when the fragments were eagerly collected by those who happened to be present. A portion they themselves took to Major Pover.
X-ray diffraction experiments on illite and bravaisite
Authors: Nagelschmidt G. 
Published: December 2006

Unpublished work carried out in this laboratory several years ago had shown that the first-order basal X-ray reflections of illite from South Wales occurred at a spacing of about 10Å both with potassium- and calcium-saturated samples. Recently Jackson and others observed that hydrated mica samples having a 10Å basal spacing when saturated with potassium, showed a 12 to 13Å. spacing after saturation with calcium. They interpreted their results by ascribing to illite a limited capacity for reversible lattice shrinkage and expansion, identical in type with that known for montmorillonite.In order to study the problem further three illite and two glauconite samples were treated with concentrated calcium chloride solutions for five weeks under frequent renewal of the solution.
On rhodonite and tephroite from Treburland manganese mine, Altarnun, Cornwall; and on rhodonite from other localities in Cornwall and Devonshire
Authors: Russell Arthur 
Published: December 2006

Of the many small manganese deposits which have in the past been worked in both Cornwall and Devonshire that of Treburland is from the mineralogical point of view by far the most remarkable, its especial interest being due to the variety of minerals which it has afforded and to the fact that it and one other are the only manganese deposits in the west of England which are known to lie on the contact of igneous and sedimentary rocks and which have consequently been vitally affected by contact metamorphism.The following observations are based on frequent visits to the spot since the year 1906, when I first stumbled across the locality, which, strange to say, has only received very cursory mention by the Geological Survey and has altogether escaped mention in mineralogical literature.
A list of catalogues of meteorite collections
Authors: Spencer L. J. 
Published: December 2006

The earliest systematic catalogue of meteorite collections is that of Otto Buchner in 1863, in which he listed 264 meteorites preserved in 89 collections. Thirty years later E. A. Wülfing, after circularizing 350 mineralogical and other collections, gave preliminary results for more than 500 meteorites with a total weight of 18,514 kilograms (18½ metric tons) preserved in 105 collections. This information was further elaborated in his valuable book in 1897, in which is given the weight in grams of individual meteorites in each collection.At that time Wülfing recognized 536 known meteorites. Now there are very many more–1347 according to the latest published list (C. F. Leonard, 1946, below) and 46 others have been noticed in ‘Mineralogical Abstracts’ since 1940. Wülfing's data, compiled for July 1893, is now, after more than half a century, much more out of date than he found Buchner's data after an interval of thirty years. To digest all the information now available would be an enormous task.
Determination of the composition of natural nephelines by an X-ray method
Authors: Smith J. V. , Sahama Th. G. 
Published: December 2006

In the course of the investigation of the nepheline-kalsilite system by Tuttle and Smith an X-ray method for determining the KAlSiO4 content of synthetic nephelines of composition (Na,K)AlSiO4 has been developed. This method is rapid and sensitive to about 1 % in composition ; details will be given in a later publication.Natural nephelines usually do not have the ideal composition (K,Na)AlSiO4, for they often contain excess silica and certain substituted atoms like Ca and Fe. We have, however, used this X-ray method on natural nephelines to see whether it is also applicable to them. If the method proved satisfactory, information on the chemical composition of natural nephelines could be rapidly obtained.
A further note On the presentation of chemical analyses of minerals
Authors: Hey Max H. 
Published: December 2006

Suppose that in the study of a mineral we have determined the cell-dimensions and the density, and made a ehemienl analysis. From these we can readily calculate the empirical unit-cell contents, which will usually approach integral values and so suggest a probable formula.But the calculated empirical unit-cell contents, being based on chemical and physical data subjeet to experimental error, will be subjeet to numerous sources of error, and in any serious study it is very desirable to have some rough idea of the probable limits of error. Unfortunately, this is a matter of considerable complexity, but the following suggestions may be of assistance, though they will doubtless be considerably improved on.
The age of fergusonite from the Jos area, Northern Nigeria
Authors: Darnley A. G. , Smith G. H. , Chandler T. E. D. , Dance D. F. 
Published: December 2006

Summary
Two fergusonite concentrates from different localities in the Jos area of Northern Nigeria have been analysed by the complete lead method and are accepted as having a mean age of 159±25 m.y.
Owyheeite from Rivertree, New South Wales
Authors: Lawrence L. J. 
Published: December 2006

SummaryOptical and other microproperties of owyheeite Pb5Ag2Sb6S15 are presented and details given of a new locality for this rare sulpho-salt. Apparent rotation of the plane of polarization (3·5°), microhardness (112 V.H.N.), and polarization effects are all very similar to those of the other feather ores, jamesonite and boulangerite. An intimate association with pyrargyrite is further noted.
X-ray, optical, and morphological observations on hodgkinsonite from Franklin Furnace
Authors: Roberts W. M. B. , Quodling F. M. 
Published: December 2006

SummaryRe-examination of hodgkinsonite by optical and X-ray methods has shown the desirability of adopting a setting different from that selected by Palache and Schaller and by Rentzeperis. In the new arrangement the b and c axes are interchanged and the original negative end of the b-axis becomes positive. A table of angles for the common forms is given, also X-ray powder data and a space group determination.
Formation of X-ray amorphous and crystalline aluminium hydroxides
Authors: Hsu Pa Ho , Bates Thomas F. 
Published: December 2006

SummaryVarious crystalline and X-ray amorphous forms of aluminium hydroxide prepared from sulphate and chloride solutions by varying the mole ratio of NaOH to Al3+ have been characterized by chemical analysis and X-ray diffraction. When the NaOH/Al ratio is 3 or 3·3, crystalline Al(OH)3 in the form of bayerite, nordstrandite, gibbsite, or mixtures is obtained in several hours. When the ratio is 2·75 or below, no Al(OH)3 is evident and the products are X-ray amorphous and remain so even after ageing for six months. Chemical analysis indicates that the amorphous precipitates are basic aluminium sulphates or chlorides. In the 0 to 2·1 range of NaOH/Al, the composition of the products is constant, being approximately Al(OH)2·2X0·8. In the 2·1 to 2·75 range, a continuous series of basic salts, of composition ranging from Al(OH)2·2X0·8 to Al(OH)2·75X0·25, is obtained.
A chondrodite–humite-spinel marble from Sørfinnset,near Glomfjord, northern Norway
Authors: Beadshaw R. , Leake B. E. 
Published: December 2006

SummaryA chemical and modal analysis of the marble, together with chemical analyses of the coexisting spinel and the chondrodite-humite mixture are given. The spinel, a 8·101 ± 0·001 Å, n 1·731 ± 0·003, is much richer in iron (Niggli's mg 0·90), than the humite mixture (mg 0·99), which agrees with the only previous analysis of a coexisting spinel and humite mineral. It was not possible to separate the two humite minerals from each other and analyse them, but the analysis of the mixture shows less iron than any previously analysed chondrodite or humite; the composition is very near to that of humite although the mixture contains at least 50 % chondrodite. It is pointed out that there are serious discrepancies between the chemical analyses of some of the humite minerals and their accepted structural formulae. The possibility that some humite minerals contain irregular numbers of olivine and Mg(OH,F)2-TiO2 layers would fit the available chemical analyses of the humite minerals very well but more structural work is needed as the present scanty X-ray results do not confirm this view. It is suggested that Ti substitution in the humite minerals is primarily controlled by the availability of F in the rock.
The metamorphism of amygdales at 'S Airde Beinn, northern Mull
Authors: Cann J. R. 
Published: December 2006

SummaryAmygdales found metamorphosed in the aureole of the volcanic plug at 'S Airde Beinn, northern Mull, may be divided into three classes by their behaviour on metamorphism. The first class, characterized by the original dominant presence of zeolites, forms feldspar readily. It is related to a type, composed to a greater degree or entirely of ferromagnesian minerals, which seems to have formed by the infilling of originally void amygdales during the recrystallisation of the basalts. The second class, originally containing dominant gyrolite, forms first reyerite and then wollastonite on metamorphism, the wollastonite-filled amygdales being enveloped in a rim of aegirine-augite from the earliest stages owing to reaction between the wollastonite and the basalt. The third class originally contained calcite, now represented by the anhydrous calcium silicates larnite, rankinite and wollastonite. These minerals form concentric monomineralic zones decreasing in Ca/Si ratio outwards. Later reaction has led to the replacement of both basalt and calcium silicates by melilite. Thin aegirine-augite rims surround the amygdales.
Study of the reaction CaSO4.½H2O (β-hemihydrate) = CaSO4 (β-soluble anhydrite)+½H2O in the temperature range 20–100° C
Authors: McConnell J. D. C. 
Published: December 2006

SummaryA thermogravimetric vacuum microbalance has been used to study the reaction between β-soluble anhydrite and water vapour in the temperature range 20–100° C. Equilibrium water-vapour pressures for the hydration reaction in this temperature range were determined directly and have been compared with available data obtained by Kelly, Southard, and Anderson (1941) in the temperature range 80–120° C. The kinetics of the hydration and dehydration reactions have also been studied in a series of isothermal experiments with varying water-vapour pressure. These experiments indicate that in a vapour-pressure range close to the equilibrium value very low rates for both hydration and dehydration are observed. Outside this range of vapour pressures both hydration and dehydration rates increase suddenly and show an approximately linear increase with imposed water-vapour pressure.At low temperatures (25° C) the dehydration reaction has an associated activation energy of approximately 10 kcal mole−1. In the same temperature range additional, physical adsorption of water vapour by the specimen was noted.
Pyroxene relations in two Hawaiian hypersthene-bearing basalts
Authors: Muir I. D. , Long J. V. P. 
Published: December 2006

SummaryA preliminary account is given of an optical and electron-microprobe investigation into the pyroxene relations of Hawaiian hypersthene-bearing lavas. It is shown that the clinopyroxene jackets to the phenocryst hypersthenes consist of strongly zoned augite, not pigeonite as formerly believed; the compositional range of this pyroxene is approximately the same as that of the groundmass augite phase. Groundmass pyroxene relations are complex; in one case two distinct pyroxene phases, augite and pigeonite occur, in the other all compositions lying between augite and pigeonite are encountered.
Oriented overgrowth of hematite on beta-alumina
Authors: Segnit E. R. 
Published: December 2006

SummaryAn alkali-alumina-silica slag from the interior of a kiln used for the firing of refractories was found to contain recrystallized mullite, corundum, and beta-alumina. Isolated areas of the slag were also rich in iron oxides; in these areas beta-alumina crystallized from the melt as hexagonal plates, and at a later stage small hexagonal plates of bematite grew on the 0001 face of the beta-alumina plates in a regular fashion.
Chemical analysis of olivines by the electron microprobe
Authors: Smith J. V. , Stenstrom R. C. 
Published: December 2006

SummaryThirty-one natural olivines, of which 25 had been previously analysed by wet chemical methods, have been analysed for Mg, Fe, Mn, Ca, Ni, and Co by electron-microprobe techniques. The totals of the olivine molecules Fo, Fa, etc., calculated from the above metals vary from 97·6 to 101·5 with a mean of 99·6%. Twenty-one of the specimens had been used previously by Yoder and Sahama to prepare a determinative curve between mole per cent. Fo and the lattice spacing d130. Yoder and Sahama had found that the data for natural olivines showed large random displacements from a straight line, and that the best straight line deviated for low Fo values from that for synthetic olivines. A plot of Fo determined from the microprobe vs. d130 corrected for lattice expansion caused by Ca and Mn shows no systematic deviation between natural and synthetic specimens, and only small deviations from the best continuous curve (maximum 4% in Fo assuming no error in d130). The maximum contents found for Mn, Ca, Ni, and Co were 3·2, 0·54, 0·33, and 0·03%, respectively. For these minor constituents, some of the wet chemical analyses agreed very well with the microprobe results while others showed large deviations. Although the substitution of Ca is small, it can affect considerably the determination of mole per cent. Fo from d130.After specimen preparation and calibration have been carried out, microprobe analyses for most major and minor (but not trace) elements in common silicates can be made with an accuracy of about 0·5 to 5% of the amount present in about one minute for each group of three elements. Although standard chemical methods applied to large homogeneous samples will retain their fundamental reference value, microprobe techniques with their high spatial resolution, relative freedom from contamination problems, high speed, and moderate to good accuracy promise to revolutionize analytical programmes in mineralogy and petrology.