bluuebunny/crossref_metadata_2025 huggingface dataset:
The separation of clay mineral fractions with linear heavy liquid density gradient columns
Authors: Halma G.
Published: December 2006

Because of increased interest in mineralogical analysis of soils a rapid, generally applicable method to separate clay minerals is needed, and such a method is described here. The technique is a modification of the heavy liquid density gradient centrifugation method which is commonly applied in mineralogical practice. Modifications are:

(1)

The use of suitable surface active agents to overcome the flocculation problem.

(2)

The use of the ultra centrifuge at about 33,000 g to hasten sedimentation.

(3)

The use of a linear density gradient which supplies in addition a quick identification of the mineral composition.

Preliminary experiments, evaluating different variables (e.g. cation form, ultrasonic treatment, influence of surfactant), reveal the scope and limitations of the procedure presented.

Clay minerals of different density can be separated. However, if the clay minerals of a mixture have overlapping densities, or if they contain a series of mixed-layer minerals, only a broad fractionation is possible. This is shown by X-ray diffraction and electron microscope studies of isolated zones (or parts of them) which develop in the centrifuged density gradient columns containing various pre-treated natural clays or clay mixtures.
The Adsorption of Poly(Ethylene Glycols) on Clay Minerals
Authors: Parfitt R. L. , Greenland D. J.
Published: December 2006

Poly(ethylene glycols) of molecular weights 200 to 20000 were strongly adsorbed on montmorillonite from aqueous solution. Free energies of adsorption calculated from the adsorption isotherms became more negative with increase in molecular weight and the entropy change became increasingly positive, probably due to a net desorption of water from the clay surface as the organic compound was adsorbed. The adsorption of the higher molecular weight polymers caused an increase in the interlamellar separation. The effect of the exchangeable cation on the adsorption followed the order Cs > Na > Ca > Al, indicating that the cation retained its hydration shell and did not form a direct association with the adsorbed organic molecules. Some evidence was obtained that 'water bridges' were formed between exchangeable calcium an aluminium ions and the ether groups of the polymers.
Clay Minerals Associated with the Precambrian Gowganda Formation of Ontario
Authors: Tank R. W. , McNeely L.
Published: December 2006

X-ray analyses indicate that chlorite, illite and mixed-layer chloritesmectite are present in the < 2μ fraction of the Precambrian Gowganda Formation near Bruce Mines, Ontario. The mixed-layer material is restricted to the porous graywacke sandstones and is epigenetic in origin. The chlorite and illite are ubiquitous and may reflect high-grade diagenesis, low-grade metamorphism or a source rich in these minerals.
The rheological properties of dispersions of Laponite, a synthetic hectorite-like clay, in electrolyte solutions
Authors: Neumann B. S. , Sansom K. G.
Published: December 2006

Dispersions of Laponite clay in various electrolyte solutions have been studied. In the total absence of electrolyte the synthetic clay forms a sol at 2% concentration. All cations cause gelling and flocculation.

It has been found that for any given clay concentration the yield value of the dispersions at equivalent flocculation level is the same for all electrolyte solutions, making it possible to study all types of dispersions at a standard level of flocculation.

At standard level of flocculation, the yield values have been found to follow exponential relationships with clay concentration with a break in the curves occurring at about 1·6% clay concentration. It is postulated that the break in the yield value curve occurs when enough clay is present to form a card-house structure. The plastic viscosities show a linear relationship with concentration and indicate high effective dispersed volume fractions at low clay concentrations.

When comparing the flocculating effects of different cations at fixed clay concentration, an empirical relationship has been found between cation concentration giving standard flocculation level, cation valency and radius.
The Coalgate Bentonite. A ferriferous-beidellite deposit from Canterbury, New Zealand
Authors: Carlson J. R. , Rodgers K. A.
Published: December 2006

The Coalgate Bentonite deposit has been formed by the alteration of cryptocrystalline basaltic ash erupted in Upper Miocene to Pliocene times and deposited in a freshwater lake on a land surface of earlier tholeiitic flows. Physical and chemical analysis shows the bentonite to consist essentially of non-swelling (Ca2+ and Mg2+) ferriferous-beidellite with minor ferriferous montmorillonite. The process of montmorillonitization probably involved a crystal chemical structural reorganization without solution or precipitation and occurred in a mildly alkaline environment in which initial reducing conditions become oxidizing.
Palygorskite—by direct precipitation from a hydrothermal solution
Authors: Furbish W. J. , Sando T. W.
Published: December 2006

Palygorskite, associated with aragonite, occurs as a fracture filling in a dunite body that has been intruded by felsic pegmatites. The palygorskite formed by direct precipitation from solutions given off by the pegmatite. Aluminium, calcium and silicon were provided by the pegmatite solutions while magnesium was derived from the serpentinization of the dunite along the host fractures. No direct replacement took place.
Current and future trends in clay mineralogy—a review
Authors: Brindley G. W.
Published: December 2006

Progress in science is not a linear function of time but resembles more closely a sigmoidal process in which new trends depend on the nucleation of new ideas and the re-activation of older studies. New and improved instruments, particularly electron microscopes and microprobes, infrared spectrometers and atomic absorption analysers have been the nucleating agents for many new lines of investigation. The interdisciplinary nature of clay mineralogy makes communication between different areas of study very important and the clay mineral societies have an important part to play in this respect.

In the future, renewed efforts to obtain a convenient and reliable method of quantitative mineral analysis are likely to be made. Crystal structure analysis will be directed increasingly towards the study of order and disorder in cation distributions, layer charges, and layer stacking arrangements. Studies of domain structures in layer silicates will continue, and further refinements in mixed-layer structure analysis can be expected. Infrared spectroscopic analysis will increasingly become a major tool. The study of clay mineral synthesis and alteration in nature and in the laboratory shows signs of important re-activation. Clay-organic studies are developing in many directions.
A study of the birefringence exhibited by celadonite solutions subjected to electric fields
Authors: Baily E. D.
Published: December 2006

This paper reports an electric birefringence study on dilute solutions of the clay mineral, celadonite. The results show that celadonite particles in solution have the form of rectangular platelets and are characterized by a permanent dipole-moment perpendicular to the plane of the platelet and an induced dipole-moment in the plane of the platelet along the longest dimension. It is suggested that the permanent dipole-moment is an inherent property of the atomic structure of the platelet, whilst the induced dipole-moment is a consequence of the ion-atmosphere surrounding the celadonite particles. The paper also demonstrates the usefulness of electro-optic techniques in studying problems in clay minerology.
Clay mineral formation under lateritic weathering conditions
Authors: Harder Hermann
Published: December 2006

Amorphous hydroxides of Al, Fe, Mn, Mg, Zn, Co, Ni, etc., are capable of coprecipitating SiO2even from very dilute (weathering) solutions. Silica minerals form only in those precipitates from solutions undersaturated with respect to amorphous silica (100 ppm SiO2at 20°C). With higher SiO2concentrations the precipitates remain amorphous. The size of the cations should allow 6-fold coordination and giving a brucite-like layer. Most suitably sized octahedral ions are Mg, Zn, Ni, Co and Fe2+(size 0·78–0·82 Å), and chemically pure three- and two-layer clay minerals with these ions are easily synthesized. With a relatively high content of silica in solution (60 ppm SiO2with 1–2·5 ppm metal) several smectite minerals could be synthesized. With a low content of silica in solution (5–20 ppm SiO2andca. 2 ppm metal) the serpentine minerals, could be synthesized.

It is possible to crystallize the difficult to form Al-clay minerals in a solid solution with these more easily synthesized clay minerals.

Clay minerals with the heavy metal ions of Ni, Co, Zn, and with Cu, Cr, etc., can be found in the weathering zone of Gossan and in the lateritic weathering crust of ultrabasic rocks.
Étude des produits d'altération fumerollienne et météorique a vulcano (Iles Éoliennes, Italie)
Authors: Monaco A. , Valette J. N.
Published: December 2006

Les auteurs étudient les produits de l'altération fumerollienne et météorique de Vulcano, Iles Eoliennes, Italie. Ces produits sont étudiés par diffraction des rayons X, analyse chimique classique, microscopie électronique et microsonde.
Electrical conductivity of a montmorillonite-organic complex
Authors: Kato C. , Kuroda K. , Hasegawa K.
Published: December 2006

Volume 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

An 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

Dans 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

Porosity 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

Sorption 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

Measurements 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.
Sedimentary sepiolite of the early Permian period in south China
Authors: Deyi Liu
Published: December 2006

In 1947, based on field observations and some chemical data, the Leping white earth was first recognized as a sepiolite clay of marine origin and of early Permian age. Later investigations in the 1960s using DTA, XRD and EM confirmed this identification (Zhang Renjun, 1984). Recently, in the ‘Science Spring’, new sepiolite clay deposits have been found in south China and it has become apparent that sedimentary sepiolite in this region is closely connected with the marls of the Lower Permian system.
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.
On Fermorite, a new arsenate and Phosphate of lime and strontia, and Tilasite, from the manganese-ore deposits of India
Authors: Herbert Smith G. F. , Prior G. T.
Published: December 2006

Analyses of Indian manganese-ores generally show the presence of small amounts of arsenic. The form in which this constituent occurs was discovered by Dr. L. Leigh Fermor in the course of his investigations of these well-known deposits. At two different localities crystalline arsenates were found. One of these occurrences is at the Sitapar deposit in the Chhindwara district, Central Provinces. The pinkish-white to white arsenate found there is the new mineral to which we have given the name fermorite. The other locality at which an arsenate was found is Kajlidongri, Jhabua State, Central India. The pale-green arsenate, somewhat resembling apatite in appearance, which occurs at this locality has been found by us to be identical with the tilasite from Sweden described by Sjögren.
On Rathite and its variety, Wiltshireite
Authors: Lewis W. J.
Published: December 2006

The main portion of this memoir as far as it relates to wiltshireite was in the Editor's hands in January, 1911 ; but before it was sent by him to press I learnt that Mr. R. H. Solly had, at the Anniversary Meeting of the Mineralogical Society in 1903, described an unnamed crystal, which, from the statement made to the Society on March 21, 1911, and published in the ‘Mineralogical Magazine’ (1911, vol. xvi, p. 121), is undoubtedly the same substance as that named by me in August, 1910, wiltshireite. In the statement of March, 1911, Mr. Solly pointed out the striking relation of the crystals of wiltshireite to those of rathite ; and suggested that the latter is ohlique and not orthorhombic, as described in this Magazine (1901, vol. xiii, pp. 77-85).
Calcite crystals from a water-tank
Authors: Gwinnell Russell F.
Published: December 2006

A crystalline deposit of sufficient interest to warrant description was brought to the authore notice by Mr. Henry Preston, F.G.S., who has recently described its mode of occurrence. The material consists of a white, glistening, crystalline powder, or a sand-like aggregate of minute crystals. It was deposited in a water-tank into which water was led through an old leaden pipe, over a mile in length, from a spring rising from the basal ferruginous beds of the Marlstone (Middle Lias) ill Belton Park, north of Grantham, Lincolnshire. The sand was deposited in the tank as a conical heap, spreading over a base of perhaps four square yards and reaching a height of seven or eight inches at its summit.
Notes on the occurrence of Bertrandite at some new localities in Cornwall
Authors: Russell Arther
Published: December 2006

In 1904 Professor Bowman described the occurrence of bertrandite at the Cheesewring Quarry, Linkinhorne, Cornwall; the mineral having been then recently discovered there by Mr. F. H. Butler. The following notes contain an account of the character and mode of occurrence of the same mineral at four additional localities in Cornwall.
On the occurrence of Bornite nodules in shale from Mashonaland
Authors: Mennell F.P.
Published: December 2006

About the middle of 1911, I was commissioned to report on a copper mine known as the Umkondo, situated in the south-east of Mashonaland, the eastern province of the territory of Southern Rhodesia. The mine is in a very out-of-the-way spot, about 120 miles from Odzi station, the nearest point on the railway, and to reach it took five days of somewhat rough travelling by cart.
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.
On the chemical composition of the Metearites Amana (= Hamestead) and Eagle Station
Authors: Prior G. T.
Published: December 2006

The Amana meteorite, known also as Iowa County, Homestead, and West Liberty, is fully described in O. C. Farrington's 'Catalogue of the Meteorites of North America'. After the appearance of a brilliant meteor which on the night of February 12, 1875, passed with loud detonations from S.W. to N.E. over northern Missouri and southern Iowa, about 100 meteoric stones, weighing altogether some 500 lb., were found scattered over an elliptic area of about eighteen square miles from Amana in Amahs township to Boltonville in Iowa township, both in Iowa Co., Iowa.
On Sartorite and the problem of its crystal-form
Authors: Herbert Smith G. F. , Solly R. H.
Published: December 2006

To mineralogists probably few spots in the world surpass in interest the little quarry hollowed out of the dolomite, just where the latter is cut by the Lengenbaeh, and about half a kilometre above the point where this stream ends its hurried course by joining the Binna at Imfeld, a hamlet lying in the main valley three kilometres above the village of Binn.
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.
Euclase and platinum from diamond-washings in British Guiana
Authors: Spencer L. J.
Published: December 2006

The euclase here described is not only from a new locality, but it represents an entirely new type of habit for this rare mineral, which is occasionally used as a gem-stone. The crystal aggregates present a strange resemblance to fossils, and fossils not having been found in British Guiana they were submitted to the Geology Department of the British Museum by Mr. R. P. Stewart of Georgetown, Demerara. They had been found by Mr. J. C. Menzies whilst engaged in washing for gold and diamonds in the neighbourhcod of the Kaieteur gorge on the Potaro river, a left tributary of the Essequibo. Both of these gentlemen have interested themselves in the matter and have kindly sent further material for examination.
On garnet in pelitic contact-zones
Authors: Tilley C. E.
Published: December 2006

Of the garnet group of minerals, two members only appear to have been synthesized from artificial melts, viz. melanite (L. Michel, 1892) and spessartine (L. Bourgeois, 1883, and A. Gorgeu, 1883); though grossular is once reported by E. S. Shepherd, G. A. Eankin, and F. E. Wright (1909) as being produced by reaction under pressure of calcium orthosilicate and aluminium chloride. In dry melts, pyiope is represented by a cordierite-forsterite-spinel assemblage, but no data are yet available to indicate the dry melt assemblages representing almandine. The home of almandine in sediments is the dynamically metamorphosed pelite, and its widespread regional occurrence in these crystalline schists implies a ready synthesis under the influence of shearing stress.
Smithsonite from the Rhodesia Broken Hill mines
Authors: Mountain E. D.
Published: December 2006

During an examination of zinc ores I had occasion recently to employ methods for the identification of smithsonite, and was surprised to find how scanty and indefinite are the data of its physical properties as stated in text-books. Most of the smithsonite known occurs either compact or as very small crystals many of which are of a composite nature. In this connexion Dr. L. J. Spencer recently acquired for the British Museum some very fine crystals from the Rhodesia Broken Hill mines, and he suggested that this material would be suitable for a detailed examination. These consist of two specimens obtained in 1921 from Mr. W. E. Harris [B.M. 1921, 769] and in 1923 from Dr. O. L. Brady [B.M. 1923, 619] respectively, and are portions of the same mass. Smithsonite crystals were first described from this locality by Dr. Spencer in 1908, but these crystals were minute and showed only the forms v (201̄) and s (223̄).
The Mbosi meteoric iron, Tanganyika Territory. (With Plates XIX and XX)
Authors: Grantham D. R. , Oates Frank
Published: December 2006

The meteorite is situated on the western slope of Marengi Hill, about 150 yards from the top of the hill and close to the boundary of Mr. Jennes's farm. This place is 10 miles south-east of the Mbosi mission station in Rungwe (formerly Langenburg) district. The latitude and longitude are approximately 9°7′ S., 33°4′ E. The locality lies between Lakes Tanganyika and Nyasa, south of Lake Rukwa, and about 23 miles from the border of Northern Rhodesia.
On a new method of detecting pyro-electricity
Authors: Martin A. J. P.
Published: December 2006

Introduction—pyro-electricity has been investigated by various methods. Sir David Brewster heated his crystals and brought them into contact with small, very light, insulating particles: If these adhered, the presence of pyro-electricity in the crystal was inferred. He also used a very delicately suspended brass needle. Being a conductor it was attracted to a charged crystal when this was brought near to it. Hankel placed the crystal under investigation in a small bath of copper or iron filings, which was then put into a hotair oven. The filings did not entirely cover the whole crystal, but one corner, edge, or face, whichever was required, was left exposed. A very small platinum sphere connected to an electrometer was then brought near to the exposed portion. The charge induced on the sphere was taken as a measure of the charge developed at the particular spot on the crystal opposite the platinum sphere.
An occurrence of vanadiferous nodules in the Permian beds of South Devon
Authors: Carter G. E. L.
Published: December 2006

The object of this note is to place on record an interesting occurrence of vanadiferous nodules on the coast of South Devon. I have to thank Lord Clinton, the owner of the property on which the nodules occur, for the assistance and encouragement he has given me in this matter, and Lieut.-General Sir William Furse, the Director of the Imperial Institute, for kindly arranging to have chemical analyses carried out by Miss Hilda Bennett in the Institute Laboratory. I also have to thank Mr. Thomas Crook, of the Imperial Institute, for the trouble he has taken to write up this short paper on the basis of my notes and the laboratory work done at the Institute.
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.
Metasomatism in the basalt of Haddenrig quarry near Kelso and the veining of the rocks exposed there
Authors: Tomkeieff S.I.
Published: December 2006

Haddenrig (Haddon Rig) quarry is situated three miles east of Kelso in Roxburghshire, near the road from Kelso to Mindrum in Northumberland. The rock quarried is marked on the Geological Survey Map (Scotland, Sheet 26) as a basalt intrusive into the Lower Carboniferous lavas (Kelso traps). The absence of exposed contacts excludes any direct field evidence of its intrusive character, but the appearance of the fresh basalt from the quarry suggests that it belongs to a sill or a plug, as it is in many ways similar to other intrusive basalts of the Kelso district. The evidence of the orientation of the felspar laths in the basalt is not entirely conclusive. With the exception of the northern part of the quarry where the orientation is vertical, elsewhere it is more or less horizontal. This suggests a sill. The vertical orientation of laths in the northern part of the quarry may be due either to the presence of a feeding channel or to eddies in the sill.
Minyulite (hydrous K-Al fluophosphate) from South Australia
Authors: Spencer L. J. , Bannister F. A. , Hey M. H. , Bennett Hilda
Published: December 2006

In 1908, at the close of the Franco-British Exhibition at Shepherd's Bush, London, a series of rock phosphates from various localities in South Australia was transferred to the Mineral Department of the British Museum as a present from the Government of South Australia. One large block from Wait's quarry at Noarlunga, 20 miles south of Adelaide, showed cavities lined with crusts of minute crystals. These crystals were determined goniometrically and optically in 1908 to be orthorhombic, and qualitative chemical tests showed the presence of Al, Mg, P, F, and H2O (K was missed). This evidently represented a new mineral, and it is only now that the work has been successfully completed by the three junior authors. In the meantime, however, the same mineral was discovered in Western Australia by the late Dr. E. S. Simpson in 1932, and named minyulite, from Minyulo Well. This he determined optically to be orthorhombie, and the formula was given as KAl2(OH,F)(PO4)2.3½H2O or 2K(OH, F).4A1PO4.7H2O. Crystallographic and X-ray data are now given for this species.
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.
Crystallization of basaltic magma as recorded by variation of crystal-size in dikes
Authors: Winkler Helmut G. F.
Published: December 2006

It is a familiar fact that in dikes, lava-flows, and sills the grain-size of the individual minerals normally varies according to the distance from the contacts. At or near the margins of the igneous body the grainsize is usually very much less than in the centre, and this phenomenon has been attributed to differences in the cooling-velocities at these spots. On the basis of measurements carried out by Queneau (8) the opinion seems to have been formed that the crystal-size always shows a progressive increase from the contacts towards the centre. This is not so, however, for as Lane (6) has shown, the crystal-size may increase to a maximum at a certain distance from the margin, and thereafter decrease again towards the centre of the intrusion. Apart from these investigations, carried out by Queneau and Lane, the only additioual quantitative data oil crystal-size variation known to the writer concerns a series of measurements made on an olivine-diabase by B. H. Dollen, under the direction of H. L. Alling.
Unusual dolomite from Portsoy, Banff
Authors: Harry W. T. , Patterson E. M.
Published: December 2006

A thin belt of serpentine up to 400 yards wide and about 6 miles long runs SSW. from Portsoy, Banff, and parallel to the general structure lines at that locality. Near Damhead, 1½ miles SSW. of Portsoy, an old quarry has recently been reopened in this belt and worked to a depth of 98 feet for the exploitation of talc. The general association in this quarry, stated in order of quantitative importance, is serpentine, talc, dolomite, the last being present in very minor amount but of an unusual character meriting description. In the following account the particular task of one of us (E. M. P.) has been the preparation of chemical analyses, the other author being responsible for descriptions and discussion.
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.
A suggested igneous origin for the banded granular hornfelses within the hypersthene-gabbro of Ardnamurchan, Argyllshire
Authors: Brown G. M.
Published: December 2006

The hypersthene-gabbro of Centre 2, Ardnamurchan, is intruded largely amongst sedimentary rocks. Despite this fact the majority of the inclusions are, as described by Riehey and Thomas (1930), of granulitized basic and ultrabasic igneous rocks. Recently M. K. Wells (1951) studied this problem again, but was only able to find four occurrences in which the xenolith was undoubtedly of sedimentary origin. However, he considered in some detail a problematical group known as the banded granular hornfelses and concluded that, despite four possible modes of origin, the textural and compositional evidence favoured a development through the metasomatism of sediments.
An accurate determination of the cell dimensions of bultfonteinite, Ca4Si2O10H6F2
Authors: Megaw Helen D. , Kelsey C. H.
Published: December 2006

Bultfonteinite from Bultfontein mine, Kimberley, South Africa, is a hydrated fluorine-containing calcium silicate, of approximate composition Ca4Si2O10H6F2. It was first described in 1932 by Parry, Williams, and Wright,1 who gave an account of its morphology, optical properties, composition, and chemical relationships. It is triclinic but markedly pseudo-orthorhombic. The present work consists primarily of a determination of the unit-cell dimensions, involving a more accurate evaluation of the interaxial angles than the earlier one; this is followed by some tentative suggestions about the structure.
The structure of wadeite
Authors: Henshaw D. E.
Published: December 2006

Wadeite has been found only in a suite of leucite-lamproites from the West Kimberley area of Western Australia. The leucite-bearing rocks occur at a number of isolated volcanic vents that have in every instance broken through sedimentary deposits of Permian age. The nature of the mineral, wadeite, has been described by Prider. It is a potassium-zirconium silicate occurring as highly birefringent prisms up to 1 mm. in length with hexagonal-shaped basal sections. It is invariably replaced in part along the poor pyramidal cleavages by calcite.
Dehydration of the montmorillonite minerals
Authors: Greene-Kelly R.
Published: December 2006

Studies of the effect of dehydration at temperatures greater than 150° on sorption by montmorillonites have shown that small interlayer cations such as lithium and magnesium promote an irreversible decrease in the amount of interlamellar sorption and a consequent marked fall in the cation exchange capacity as measured by conventional methods (1, 2, 3, 4). The other minerals of the group do not show this property (4), which is quite distinct from the supposed 'potassium fixation' reported in these minerals (5). This latter effect, which is small for montmorillonite, refers to the decreased rate of exchange of potassium as compared with smaller exchange cations especially after the potassium-saturated mineral has been dried at ]00° C., and has been shown to be much more marked in mica-like minerals with silicate layers of higher charge density (e.g. illites and vermiculites (6)). The amount of water sorbed by potassium-saturated montmorillonite is not significantly affected by drying at temperatures below 400° C. although it is less than that of most other montmorilIonites (3), due probably to the low hydration energy of the potassium ion (7).
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

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

Optical 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

Re-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.
Monochromator or graded spectrum filter?
Authors: Holgate Norman
Published: December 2006

The suitability of monochromators for visual applications in petrographic mineralogy is discussed, and a new and inexpensive instrument employing a graded interference filter is described.
Formation of X-ray amorphous and crystalline aluminium hydroxides
Authors: Hsu Pa Ho , Bates Thomas F.
Published: December 2006

Various 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

A 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

Amygdales 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

A 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.