bluuebunny/crossref_metadata_2025 huggingface dataset:
On Emotionally Intelligent Time Travel: Individual Differences in Affective Forecasting Ability
Authors: Dunn Elizabeth W. , Brackett Marc A. , Ashton-James Claire , Schneiderman Elyse , Salovey Peter
Published: December 2006

In two studies, the authors examined whether people who are high in emotional intelligence (EI) make more accurate forecasts about their own affective responses to future events. All participants completed a performance measure of EI (the Mayer-Salovey-Caruso Emotional Intelligence Test) as well as a self-report measure of EI. Affective forecasting ability was assessed using a longitudinal design in which participants were asked to predict how they would feel and report their actual feelings following three events in three different domains: politics and academics (Study 1) and sports (Study 2). Across these events, individual differences in forecasting ability were predicted by participants' scores on the performance measure, but not the self-report measure, of EI; high-EI individuals exhibited greater affective forecasting accuracy. Emotion Management, a subcomponent of EI, emerged as the strongest predictor of forecasting ability.
Note on the spontaneous crystallization of drops of solutions as spherulites
Authors: Chevalier Jacques
Published: December 2006

Previous experiments made by myself in the Oxford Mineralogical Laboratory on the crystallization of potash-alum had shown that a drop of supersaturated solution Of potash-alum, when left by itself, crystallized almost invariably in birefringent sphere-crystals, which represent a more soluble and less hydrated variety of that substance. It was further suggested (1) that the spontaneous crystallization of that particular substance always takes place as spherulites ; and (2) that this spherulitie growth is indicative of a sudden change in the solution, which is passing from the metastable state for ordinary alum (in which ordinary octahedra, when introduced, grow by themselves) to the labile state (in which the alum crystallizes as a rectangular network of needles).
On the changed composition of an anorthoclase-bearing rock-glass
Authors: Hawkes L. , Harwood H. F.
Published: December 2006

The present investigation began with an attempt to isolate and analyse the small sparse anorthoclase insets (t)henocrysts) of the chilled glassy selvage of a felsite dike. On comparison of the compositions of the insets and the host rock it was found that the relationship was abnormal and that the insets could not have grown in a magma represented by the glass. The composition of the felsite interior of the dike, however, represents a magma which could have yielded the anorthoclase, and full consideration leads to the conclusion that the glass, though absolutely fresh and unaltered in appearance, has suffered marked changes in composition.
On quartz-kyanite-rocks in Unst, Shetland Islands, and their bearing on metamorphic differentiation
Authors: Read H. H.
Published: December 2006

Among the many beautiful rocks of Unst, the most northerly of the Shetlands, is one composed of rosettes of pale blue kyanite set in a base of glassy quartz. This rock was mentioned by Heddle, but has never been described, nor have its genetic relationships been considered. During the mapping of Unst for the Geological Survey, opportunity was afforded of examining the field-relations of these quartz-kyanite-rocks and of collecting adequate material for study. I am indebted to Sir John Flett, F.R.S., Director of the Survey, for permission to present this account. These rocks have a considerable intrinsic interest; in addition, their investigation is closely concerned with certain general problems in metamorphism, especially those connected with metamorphic differentiation. The present paper is therefore divided into two portions, the first dealing with the description and origin of the Unst rocks, and the second with more general aspects.
A possible source of error in the determination of symmetry from optical extinction-angles
Authors: Hey Max H.
Published: December 2006

During an optical examination of many mesolite crystals with a view to a determination of their symmetry, the author was puzzled to find that whereas mesolite has generally been described as anorthic, on optical evidence, he could detect no trace of inclined extinction in the prism zone. A. Cavinato (1926) 1 and G. Ceshro (1909) 3 had already made similar observations. Further study revealed the probable causes of the discrepancies, and as these sources of error, and the precautions necessary for their avoidance, receive little or no mention in the principal text-books, an account of them might be of some use.
Portlandite, a new mineral from Scawt Hill, Co. Antrim
Authors: Tilleu C. E.
Published: December 2006

Though calcium hydroxide has long been known as a product of hydrolysis of Portland cement, reliable data on its physical and optical properties were not available until Ashton and Wilson prepared this substance artificially and had examined crystals developed in rugs in old cement briquettes. In examining some recently collected larnite-spurrite-rocks from Scawt Hill the writer observed crystals now shown to be Ca(OH)2 as constituents of aggregates composed mainly of coarsely grained afwillite, forming infillings in these contact-rocks.
Shower of meteoric stones in the neighbourhood of the village Kuznetzovo, West Siberia, on May 26, 1932
Authors: Dravert (II. JI. Драверт) P. L.
Published: December 2006

The end of October 1932 information was received at the West Siberian Museum in Omsk that in May 1932 a meteorite fell in the village of Kuznctzovo (Кузнецово), 140 km. east by north from Omsk. On November 3-7, together with my assistant P. Serov, I investigated the matter on the spot. In March 1933 some further information was received, and I am now able to make the following preliminary communication.
Zoning in plagioclase felspar
Authors: Phemister James
Published: December 2006

During the examination of the basalts of Calciferous Sandstone age which are mapped on the one-inch Sheet 23 (Hamilton, Lanarkshire) Scotland, the peculiarities of zoning exhibited by the porphyritic felspar were studied in some detail. As only a summary of the details is possible in the memoir explanatory of the geology of this Sheet, the description of the zoning is offered here, and some conclusions regarding the magmatic history of the zoned felspars are presented.
A new meteoric stone from Silverton, New South Wales
Authors: Spencer L. J.
Published: December 2006

Unfortunately nothing is known of the history of this stone. It was found in 1933 by Mr. R. Bedford in the old museum at Port Adelaide in South Australia. Attached to the specimen is a small label with the number 23, and accompanying it was a card giving in faded writing the information '(23) Meteoric stone from Silverton'. The Port Adelaide Museum has been in a neglected condition for thirty years, and recently it has been decided to reorganize it as a Nautical Museum, and to discard all mineral and miscellaneous material.
Basaluminite and hydrobasaluminite, two new minerals from Northamptonshire
Authors: Hollingworth S. E. , Bannister F. A.
Published: December 2006

White mineral coating joint-faces in quarries in the Northampton ironstone (Inferior Oolite) was long ago recorded as allophane. W. D. Herman who determined the mineral from the surface of a sandstone rock in a quarry opened in 1871 also analysed an unnamed white earthy mineral from crevices in the ironstone and obtained a composition close to that of fully hydrated halloysite.

During the six-inch geological survey of that ironstone field in 1939–44 the occurrence of similarly situated white incrustations and joint infillings was found to be widespread especially in the shallow workings where the ferrous minerals chamosite and chalybite have been oxidizedto produce a limonitie ore.
Baryte-bearing nodules from the Middle Lias of the English east midlands
Authors: Taylor J. H.
Published: December 2006

The Middle Lias of Rutland, east Leicestershire, and north-west Northamptonshire was described by Judd in 1875 as comprisingan upper ferruginous member—-the Marlstone Rock Bed-—and a lowerargillaceous division of blue clays, often micaceous or sandy, and carryingbands of 'septaria' and of 'ironstone balls'. In the septaria he recordedthe occurrence of 'specular-iron, zinc-blende and pyrites'.

During the six-inch survey of one-inch New Series sheets 157 (Stam-ford) and 171 (Kettering) together with the adjacent parts of sheets 156(Leicester) and 170 (Market Harborough) a considerable area of thelower argillaceous division was mapped.
New data on the slag-minerals nagelschmidtite and steadite
Authors: Segnit E. R.
Published: December 2006

In 1937 G. Nagelschmidt described a new silicophosphate mineral obtained from basic slag. It resembled the earlier described silicocarnotite (A. Carnot and A. Richard, 1883; D. P. Riley and E. R. Segnit, 1949) in its solubility in citric acid. Nagelschmidt gave optical, chemical, and X-ray data which indicated that the material had a composition of approximately 7CaO.P2O5.2SiO2, and agreed closely with a phase reported by G. Trömel (1943) in his investigation of the system CaO-P2O5-SiO2. The material was further considered by M. A. Bredig (1941), who published cell dimensions worked out from powder photographs, assuming that nagelschmidtite was a solid solution of tricalcium phosphate in a predicted high-temperature hexagonal form of dicalcium silicate. R. L. Barrett and W. J. McCaughey (1942) gave further data, chiefly connected with phase relationships in the binary system Ca2SiO4-Ca3P2O8. Finally, S. O. Agrell (1946) published further data on the slag mineral, giving the chemical analyses and optical properties of two samples, together with a discussion of the phase relationships of the material in slags, and hence in the binary system mentioned above. The name 'nagelschmidtite' is due to Barrett and McCaughey.
A comparison between the parageneses of Fennoscandian limestone contact minerals and those of the Alnö alkaline rocks, associated with carbonates
Authors: von Eckermann Harry
Published: December 2006

Pargas in Finland and MansjSand and Tennberg in Sweden are the only three Fennoscandian contact metamorphic limestone occurrences of which systematic accounts have been published; in the first case by A. Laitakari (1) and in the two latter ones by the present author (2, 3). A more complete analytical programme would have been desirable, and unfortunately many of the analyses are incomplete, especially as regards the determination of the valency of the iron. Nevertheless, the available data, and a few I have been able to add later, may suffice to give us a general idea of the paragenetical and chemical differences between these Archaean mineral parageneses and those of much younger age which occur in connexion with the limestone masses associated with the alkaline occurrence of Alnö in Sweden.
Paralaurionite
Authors: Palache Charles
Published: December 2006

Paralaurionite from a new locality, the Mammoth mine, Arizona, is described. X-ray study and chemical analysis confirm the original characteristics of the mineral as described in 1899 by G. F. Herbert Smith. Measurements are given which establish new forms on crystals from Arizona and also on crystals from a South American locality. A complete angle table for twenty-eight forms is presented.
The statement of chemical analyses of stony meteorites and the interpretation of the analyses in terms of minerals
Authors: Wahl Walter
Published: December 2006

In earlier analytical work on stony meteorites the analytical results were given in a number of different ways. Not only the principles, but also the methods used in the calculation of the mineral composition as derived from the chemical analyses, were of a different kind in almost every description of a stony meteorite. The same remarks of course apply to a certain extent also to the older descriptions of terrestrial rocks. The publications on the 'Quantitative [(American) system of[ classification of igneous rocks' (1) and some publications by Henry S. Washington, especially a paper on 'The statement of analytical results of rock analyses' (2), contributed greatly to the unifying of the methods of representing the results of chemical analyses of rocks and calculating their mineral composition. Later on other systems for the statement and calculation of rock analyses have been introduced by other petrologists, especially by Paul Niggli, and all this work, taken together, has greatly contributed to clarification of the different ways in which the results of rock analyses can be stated and made use of in the petrological study of rocks.
The petrology of the evaporites of the Eskdale No. 2 boring, east Yorkshire. Part III. The upper evaporite bed
Authors: Stewart F. H. , Vincent E. A.
Published: December 2006

The rocks of the lower and middle evaporite beds of the Permian, passed through by the D'Arcy Exploration Company's boring in 1938-39 (Lees and Taitt, 1946), have been described in earlier communications (Stewart, 1949, 1951). The present paper deals with the petrography of the upper evaporite bed (3655-3860 feet below surface).
The paragenesis of sylvine, carnallite, polyhalite, and kieserite in eskdale borings nos. 3, 4, and 6, north-east yorkshire
Authors: Armstrong G. , Dunham K. C. , Harvey C. O. , Sabine P. A. , Waters W. F.
Published: December 2006

The confirmation of the presence of potassium salts in the Permian evaporites beneath the Whitby district, first found in the D'Arey Exploration Co.'s Eskdale no. 2 (Aislaby) boring (G. M. Lees and A. H. Taitt, 1945), and the discovery by Imperial Chemical Industries in their Eskdale no. 3 (Sleights), no. 4 (Sneaton), and no. 6 (Upgang) borings that these salts exist in workable quality and quantity, has been recorded in a recent historic paper by Dr. A. Fleck (1950). The successful outcome of this boring campaign may well lead to the outstanding development of the present century in economic mineralogy in Britain.
The clinopyroxenes of the Skaergaard intrusion, eastern Greenland
Authors: Muir I. D.
Published: December 2006

During the past twenty years considerable attention has been given to the compositions of the pyroxenes from basic igneous rocks. Hess (1941) reviewed the courses of crystallization of pyroxenes from mafic magmas and drew a trend line for the lime-rich clinopyroxenes. The present investigation was undertaken primarily to determine more closely the trend in the ferroaugite region, for here Hess's trend was based on the analyses of two pyroxenes from the Skaergaard intrusion and both of these are now known to be somewhat unusual types. The Skaergaard intrusion which is a strongly fractionated gabbroic complex is Particularly suitable for this study of the ferroaugites. Fifteen new analyses have been made for this investigation and twenty-three analyses of the pyroxenes from this intrusion are now available. Using nineteen of these, new trend lines have been drawn (fig. 1) for the Skaergaard clinopyroxenes.
A note on the occurrence of columbite in the Meldon aplite, Devonshire
Authors: von Knorring Oleg
Published: December 2006

During a departmental excursion to South Devon in April 1951, material was collected from the Meldon aplite quarry near Okehampton, to the north-west of the Dartmoor granite, which on examination has proved to contain the mineral columbite. The mineral is present only in very small amounts and as extremely minute crystals; nevertheless its presence is of considerable interest in that this appears to constitute the first authenticated record of the occurrence of a mineral of the columbite-tantalite series in Britain.
On the occurrence of varlamoffite (partially hydrated stannic oxide) in Cornwall
Authors: Russell Arthur , Vincent E. A.
Published: December 2006

As long ago as 1906 I had noticed a yellowish clay-like mineral occurring somewhat abundantly at both Cligga mine, Perranzabuloe, and at Bunny mine, St. Austell. From its appearance the mineral did not look particularly interesting, neither did it suggest being one containing a metal, and for these reasons no attempt was made to determine its character. In a paper read before this Society in 1937 I mentioned this yellowish clay-like substance as occurring associated with rashleighite at the Bunny mine. Soon after the publication of this paper in 1948 I received a letter from Monsieur N. Varlamoff in the Belgian Congo saying he had seen my reference to the 'yellowish clay-like substance' (p. 356) and suggested it might possibly be identical with the mineral varlamoffite which he had recently discovered in the Belgian Congo and which had been named after him, his description of the mineral with analysis, mode of occurrence, and localities having been published in 1948.
The ledmorite dike of Achmelvich, near Lochinver, Sutherland
Authors: Sabine P. A.
Published: December 2006

In the Geological Survey memoir a dike is recorded cutting the Lewisian gneiss near Achmelvich, north-west of Lochinver, Sutherland. At the time the mapping was carried out no thin section was prepared of the rock, and the dike was presumed to be a continuation of the Canisp porphyry dike which is exposed in the river Inver near Lochinver and farther south-east.

During an investigation of the post-Cambrian sills and dikes of Assynt and the adjoining districts of north-west Scotland, the writer examined the Achmelvich dike in some detail and recognized its affinities with the nepheline-syenites. It is the purpose of the present note to describe the field occurrence and petrography of the dike.
Dalyite, a new potassium zirconium silicate, from Ascension Island, Atlantic
Authors: Van Tassel R. , Hey M. H.
Published: December 2006

Ejected blocks of piutonic igneous facies have long been known in the trachytic and basaltic tufts of Green Mountain and Middleton Peak on Ascension Island, and a petrographic account of them has been recorded by Professor R. A. Daly in his memoir on the geology of Ascension Island.
On the occurrence of turquoise in Cornwall
Authors: Russell Arthur
Published: December 2006

In my description of the mineral rashleighite, which was given in this magazine in 1948, I mentioned that most of the mineral from the Bunny mine, St. Austell, was in colour light blue-green, but that it was also sometimes true turquoise-blue. Likewise, at the Castle-an-Dinas wolfram mine, St. Columb Major, there occurred rarely in addition to the blue-green rashleighite a true turquoise-blue mineral which was first assumed to be turquoise and later rashleighite. It has now been found, however, that this turquoise-blue mineral is in fact true turquoise, and distinct from the green rashleighite, Specimens of this turquoise were found at the Bunny mine, associated with varlamoffite.
The unit-cell contents of anthophyllite
Authors: Francis G. H.
Published: December 2006

Conclusions concerning the unit-cell contents and chemical formula of a mineral are all too often drawn from a small part of the available data. A procedure is outlined by which any chemical analysis for which a density is available can be utilized, provided X-ray data are available for a reasonable range of analysed specimens. The effects of possible errors in the determination of water, and in the assessment of essential and non-exsential water, are discussed both qualitatively and quantitatively.

A survey of all available data for anthophyllite has not disclosed any specimens in which the number of oxygen atoms per unit cell is significantly in excess of 96 with the possible exception of the Glen Urquhart gedrite and the Edwards (New York) material. But it is certain that the number of cations per unit cell is normally well in excess of 60 (partial occupation of the A lattice positions), and that, although ‘excess’ water in sonic fibrous anthophyllites may be adsorbed impurity, the number of hydroxyl groups in others is well in excess of 8 per unit cell; it is also fairly clear that the number of hydroxyl groups may fall below 8 per unit cell.
Subsolidus data for the join Ca2SiO4—CaMgSiO4 and the stability of merwinite
Authors: Roy Della M.
Published: December 2006

A study of phase equilibria among the orthosilicates on the Ca2SiO4—CaMgSiO4 join was undertaken with the use of hydrothermal techniques in the temperature range 600–900°C. at water pressures from 1000 to 15000 psi. Monticellite, merwinite, and Ca2SiO4 crystallize as pure phases throughout this temperature range, and intermediate compositions contain mixtures of the end members. Powder X-ray diffraction data obtained on the mixtures indicate no change in lattice dimensions from the end members. Hence, very little or no solid solution is indicated at these temperatures. Ca2SiO4 was crystallized as the γ-form below 675°C. (at 2000 psi) and the β-form above this temperature (presumably having inverted from the α′-form on cooling to room temperature). Infra-red absorption spectra obtained on the compounds γ-Ca2SiO4, β-Ca2SiO4, merwinite, and monticellite show characteristic differences in the pattern within the 9–13 micron region. All the data thus appear to confirm merwinite as a unique compound stable in the temperature range studied.
The Holmes effect and the lower limit of modal analysis
Authors: Chayes F.
Published: December 2006

Thin-section analysis is essentially an areal measurement, the measurement area usually being the upper surface of the section. If transmitted light is used for the measurement, the apparent areas of opaque grains will in general be somewhat larger than their true areas on the measurement surface. For strictly spherical opaque particles in a transparent matrix the expected excess of apparent over true area is shown to be (πr2k)/(2r + k) where r is the spherical radius and κ is the thickness of the thin section. A table shows the relation between true and apparent area as a function of r/k.
Collophane from the chalk
Authors: Brown George , Ollier C. D.
Published: December 2006

Sixteen samples of Middle and Upper Chalk from the Chilterns yielded what appear to be fragments of fish scales, spines, and bones, which consist of collophane. X-ray examination by the powder method shows that the material has an apatite-type structure with cell dimensions close to those previously reported for francolite. Examination of single grains shows that the optical anisotropy is due to preferred orientation of the c-axes of the crystallites and this direction corresponds to the faster vibration direction. Such grains are found to be pseudouniaxial negative. Preferred orientation could not be detected in isotropic grains.
The nature of carphosiderite and allied basic sulphates of iron
Authors: Moss A. A.
Published: December 2006

The composition of carphosiderite has been given as

H2O.Fe3(SO4)2(OH)5H2O

and like the jarosites is characterized by a ferric iron to sulphate ratio of 3:2. It is significant not only that this formula was worked out on artificial material but also that none of the analyses so far made supports it. The present investigation shows that there is little or no evidence for the existence of a mineral with the above composition and that carphosiderites are in reality either jarosite or natrojarosite. It has long been thought that certain other minerals, namely borgströmite, utahite, cyprusite, pastréite, raimondite, apatelite, and planoferrite, were similar to, if not identical with, carphosiderite and six of these are listed with carphosiderite in Dana, Syst. Min., 7th edn. These minerals with the exception of planoferrite and the possible exception of apatelite are also jarosite or natrojarosite.
Direct measurement of standard reflectances with the microphotometer
Authors: Hallimond A. F.
Published: December 2006

A visual microphotometer depending on three polarizing screens is used to provide the primary scale for measuring the ratio of intensity between the incident and reflected beams for a prepared standard surface, which is intended for subsequent use in the ordinary procedure with the ore-microscope. A reversing mirror on the microscope stage gives reflection at quasi-normal incidence. Direct measurements on a surface of diamond confirm the validity of the Fresnel formula for a polished surface of this substance, and there is general agreement for a series of transparent bodies ranging up to 17 % reflectance. The standard is a glass-covered metallic surface with a reflectance near 50 %. For pyrite RD = 54·5 %.
Götzenite and combeite, two new silicates from the Belgian Congo
Authors: Sahama Th. G. , Hytönen Kai
Published: December 2006

A nephelinite from the extinct volcano Mt. Shaberu, North Kivu, Belgian Congo, contains two new minerals: Götzenite is triclinic with a 10·93, b 7·32, c 5·74 Å, α 90°, β 100°, γ 120°; the unit-cell contents approximate to (Ca,Na,Al)7 (Si,Ti)5O15F3·5, and the optical constants are α 1·660, β 1·662, γ 1·670, 2Vγ 52°; sp.gr. 3·138. Götzenite is related to the rinkite series, and, less closely, to wollastonite and pectolite. Combeite is rhombohedral, space-group R3m, R32, or R¯3m, a 10·43, c 13·14 Å., the unit cell containing approximately 3[Na4(Ca,Al,Fe)3Si6O15(O,OH,F)2]; optically uniaxial positive, ε = ω = 1·598±0·002; sp.gr. 2·844.
Pyroxenes from the early and middle stages of fractionation of the Skaergaard intrusion, East Greenland
Authors: Brown G. M. , Vincent E. A. , Brown P. E.
Published: December 2006

Coexisting calcium-rich and calcium-poor pyroxenes have been separated from the gabbros and ferrogabbros of the Skaergaard layered basic intrusion and chemically analysed. Nine new analyses of augites, three of inverted pigeonites, and one of orthopyroxene are presented, together with optical properties. The trend of crystallization of the augites is different from that drawn by previous investigators. The stages at which the orthopyroxene and pigeonite begin and cease to erystallize are defined, and the sub-solidus exsolution and inversion textures of the pigeonites are examined in detail. The characters of the exsolution textures and the degree of pigeonite inversion (monoclinic to orthorhombic pyroxene) are shown to change gradually with height in the intrusion, and are related to a gradual change in the interval between the temperatures of crystallization and inversion.
An investigation of two new minerals: rhodesite and mountainite
Authors: Gard J. A. , Taylor H. F. W. , Chalmers R. A.
Published: December 2006

Rhodesite, from Kimberley, S. Africa, has been examined by electron-microscope, X-ray, and other methods. The acicular crystals are orthorhombic, with a 23·8, b 6·54, c 7·05 Å.; elongation c, cleavage (100); unit-cell contents approximately (Ca,Na2,K2)8Si16O40.11H2O; optical properties α 1·502, β 1·505, γ 1·515; α = b, β = α, γ = c. With it occurs a similar but distinct fibrous mineral, which appears to be a new species for which the name mountainite is proposed; it is monoclinic, with a 13·51, b 13·10, c 13·51 Å., β 104° elongation b, cleavage (001); unit-cell contents approximately (Ca,Na2,K2)16Si32O80.24H2O; optical properties α 1·504, β 1·510, γ 1·519; β = b (elongation). Both rhodesite and mountainite show close similarities to the fibrous zeolites, mountainite in particular resembling thomsonite. The possible structural basis of these similarities is discussed.
The illite in some Old Red Sandstone soils and sediments
Authors: Mackenzie R. C.
Published: December 2006

An illite separated from an Upper Old Red Sandstone sediment at Denholm Hill Quarry, Roxburghshire, when examined by optical, X-ray, and chemical methods, appeared to be closely similar to Fithian illite. Its composition was , where M+ for the Ca-saturated sample was [(H3O)0·58Ca0·10Na0·06K1·12]. The differential thermal curve showed two peaks: one at 550° C. and the other at 600° C. (i.e. somewhat intermediate between the Fithian and Ballater illites). The dehydration curve was also intermediate. Electron-microscope examination showed rather better crystallization than in Fithian illite. The possible reasons for variation of the illite peak temperature are discussed.
The formation of supergene galena at Broken Hill, Northern Rhodesia (With Plate XXII.)
Authors: Taylor J. H.
Published: December 2006

Lead-zinc ore-bodies in dolomite at Broken Hill, Northern Rhodesia, consist of a sulphide core surrounded by an oxidized sheath. Oxidation has been proved to persist to a depth of at least 1150 ft. below surface. In the transitional zone between sulphide and oxidized ore galena forms a thin rim to relict masses of blende, and farther into the sulphide core it penetrates the blende along cracks and cleavages. Locally it comprises over 5 % of the ore. From its relations to smithsonite and willemite it is clearly supergene in origin and must have been deposited above the water table. This considerable migration of lead in the zone of weathering is believed to have occurred during a former period of aridity.
A re-examination of uigite
Authors: Sweet Jessie M.
Published: December 2006

Uigite from Uig in Skye described by M. F. Heddle in 1855 has proved on examination to be thomsonite (var. faröelite).
Mineralogy of the Silvermines district, County Tipperary, Eire. (With Plates IV to VI.)
Authors: Rhoden H. N.
Published: December 2006

The paragenesis of a suite of hydrothermal minerals (sulphides, baryte, rhombohedral carbonates, quartz, sericite, and chlorite) at four mines in this district is discussed. Of particular interest are the conversion of pyrrhotine to marcasite, which is shown to take place by loss of iron, the replacement of blende by chlorite, and the possible formation of primary goethite. The occurrence of gudmundite is recorded for the first time in the British Isles.
A differentiated boss of alkali dolerite from Cnoc Rhaonastil, Islay. (With Plates Vii and Viii.)
Authors: Walker Frederick , Patterson E. M.
Published: December 2006

An elongated boss of alkali dolerite is described having a NW. trend and measuring 800 m. by 250 m. Two main rock-types occur, an ophitic feldsparrich analeime-olivine-dolerite or leucodolerite and a tesehenite with subhedral pyroxene. The second type is intrusive into the first but the two are associated in vertical veins. Both show local banding and analcime-nepheline-syenite forms a differentiate of both. Finer grained olivine-rich dolerite resembling the crinanites of Jura occurs at the NW. extremity of the boss and probably represents the original magma. All four types have been analysed and are thought to be the products of normal crystal fractionation with slight absolute iron enrichment. The boss was apparently headed not far above the existing exposures and is considered to be of Tertiary age. The pyroxene and olivine of the leucodolerite have been separated and analysed.
X-ray study of psilomelane and cryptomelane
Authors: Mukherjee Bibhuti
Published: December 2006

Psilomelane has been shown to be orthorhombic with a 8·254, b 13·40, c 2·864 Å. by the application of Lipson's method. The indexing of powder photographs of psilomelane , where R″ includes the bivalent metals Mn, Ba, Ca, Mg, Co) indicates the space-group P21212 (D22) with one molecule per unit cell. Indexing of powder photographs of psilomelane is not satisfactory with Vaux's axes. Fermor's ‘psilomelane’ is cryptomelane, which is tetragonal with a 9·822, c 2·858 Å. Cryptomelane (KR8O16, where R stands for Mn in different valency states, partly replaced by other cations) is body-centred tetragonal with one molecule per unit cell. Fermor's stalactitic ‘psilomelane’ has an inner dull core of cryptomelane and an outer fine-grained crust of pyrolusite in each needle-shaped body.
A minor occurrence of sepiolite from Puyvalador, near Quérigut, France
Authors: Watters W. A.
Published: December 2006

Sepiolite found as a minor constituent of dolomitie marble bordering tremolite rock from the southern contact zone of the Quérigut granite is briefly described and optical data are presented. A possible paragenesis, following on break-down of the tremolite under the action of carbon dioxide, is suggested.
A method for quantitative mineralogical analysis by X-Ray powder diffraction
Authors: Mitchell W. A.
Published: December 2006

A method of quantitative analysis by photometry of X-ray powder diffraction patterns is described. Co-Kα radiation is used and absorption difficulties are overcome by using thin diluted specimens containing an internal standard. An arbitrary universal intensity scale has been established and the values for the stronger lines of a number of minerals are given. Within individual patterns these are consistent with published data obtained by counter diffractometry.
The feldspar phenocrysts of some Tertiary acid glasses
Authors: Carmichael I. S. E.
Published: December 2006

The feldspar phenocrysts of some British and Icelandic Tertiary acid glasses have been studied optically and chemically. Six new analyses of the feldspar phenocrysts are presented together with an anorthoclase from a glassy pantellerite. The analysed feldspars and all the other feldspar phenocrysts that have been examined show high-temperature optics, and confirm the results of previous investigations of plagioclase feldspar determinative curves. The relationship of the feldspar phenoerysts to the plagioclase components in the analysed residual glasses conforms to the synthetic plagioelase system, and the crystallization of feldspar in natural acid melts is considered.
The unique meteorite crater at Dalgaranga, Western Australia
Authors: Nininger H. H. , Huss Glenn I.
Published: December 2006

The first scientific examination of the Dalgaranga crater has revealed specimens exhibiting a variety of structures and compositions hitherto unknown in connexion with any meteorite crater. Excavations have yielded much-weathered specimens and permitted measurements of the form and depth of the original pit. The question of age is considered, and the impacting meteorite is thought to have been largely stony but at least in part a mesosiderite.
Ages of uraninite from two British localities
Authors: Darnley A. G. , Smith G. H. , Chandler T. R. D. , Dance D. F. , Preece E. R.
Published: December 2006

Uraninite from Geevor Mine, Cornwall, has been analysed by the complete lead method and an age of 290±7 million years has been accepted. Similar studies of uranium from Tyndrum Mine, Perthshire, give an age of 230±8 million years. The significance of the results is briefly considered.
A refinement of the dickite structure and some remarks on polymorphism in kaolin minerals
Authors: Newnham Robert E.
Published: December 2006

The crystal structure of the clay mineral dickite (Al2Si2H4O9) has been refined to a greater accuracy than that reported in an earlier analysis. Improved lattiçe parameters are: a 5·15±0·001, b 8·940±0·001, c 14·424 ± 0·002Å., β 96° 44′± 1′. The dickite structure shows several significant distortions from the geometry of the idealized kaolin layer, including deformation and rotation of the silica tetra-hedra. The most striking features of the octahedral layer are the extremely short shared edges of 2·37 Å. Although the analysis was not sufficiently accurate to position the hydrogen atoms with certainty, a model consistent with the infrared absorption spectra is proposed. The stacking sequences of kaolin-layer minerals have been considered with reference to the structural features observed in dickite. There are thirty-six ways of superposing two kaolin layers commensurate with the OH-O bonds found in kaolinite, dickite, and nacrite. The twelve sequences showing the least amount of cation-cation superposition between consecutive kaolin layers can be used to construct two one-layer cells, kaolinite and its mirror image, and twelve two-layer cells, including dickite and nacrite. The distortions of the kaolin layer introduce secondary variations in the interlayer bonding that suggest that dickite and nacrite are the most stable of the kaolin layer structures, since they possess the shortest oxygen-hydroxyl contacts.
Ages of some uranium and thorium minerals from East and Central Africa
Authors: Darnley A. G. , Horne J. E. T. , Smith G. H. , Chandler T. R. D. , Dance D. F. , Preece E. R.
Published: December 2006

The following ages determined by the complete lead method have been accepted for minerals from a number of localities: uraninite, Nkana, Northern Rhodesia, 522±15 m.y. ; brannerite, Kansanshi, Northern Rhodesia, 503±15 m.y. ; uraninite, Shinkolobwe, Katanga, 642±20 m.y. ; davidite, Mavuzi, Mozambique, 578±15 m.y.; monazite, Monkey Bay, Nyasaland, 597±25 m.y.; samarskite, north-west Kenya, 635±25 m.y. The significance of the results is briefly considered.
Solid-solution relationships in some titaniferous iron oxide ores of basic igneous rocks
Authors: Wright J. B.
Published: December 2006

Calculations are presented, based on modal and chemical analyses of titaniferous iron ore minerals from two localities (Skaergaard and Schmoo Lake). They show that Fe: Ti ratios are constant for granular aggregates of ilmenite and titaniferous magnetite formed at any one stage in the cooling history of the containing rock body. From this and other evidence it is concluded that the aggregates are the result of exsolution from original high-temperature cubic solid solutions. For the Skaergaard rocks, the problem of separately crystallized ilmenite, distinct from the granular aggregates, is also discussed.
Metamorphism and metasomatism of rocks of the Moine Series by a dolerite plug in Glenmore, Ardnamurchan (Plate XIX)
Authors: Butler B. C. M.
Published: December 2006

A small dolerite plug in Glenmore, Ardnamurchan, has metamorphosed and partially vitrified the adjacent Moine arkoses up to a distance of 6 ft. from the contact. Chemical analyses show that the glasses produced by the metamorphism have compositions close to the ternary minimum in the system NaAlSi3O8-KAlSi3O8-SiO2, indicating that they were formed by fractional fusion of a lowest-melting composition from the arkose. Alkali metasomatism in the metamorphosed arkoses resulted in an increase of Na2O and a decrease of K2O as the contact with the dolerite is approached, while an associated pelitic horizon shows an increase of K2O content. A review of other examples of thermal metamorphism of quartzo-feldspathic rocks by basic intrusions shows that movements of alkalis are very common in this type of environment, and the possible relations of the metasomatism and the fusion are discussed.
An X-ray examination of an exceptionally well crystallized kaolinite
Authors: Goodyear J. , Duffin W. J.
Published: December 2006

Specimens of kaolinite have been found in inclusions in the ferruginous deposits on the Yorkshire Coast, just north of Scalby. The excellent quality of the X-ray powder pattern suggests that this kaolinite is better crystalline than kaolinites from other localities. Although the lattice constants of the Scalby material are considered to be identical with those previously published for kaolinite, minor differences in the intensities of the X-ray reflections do occur and may be due to a less distorted structural layer in the Sealby kaolinite.
Beryllium minerals in Cornwall and Devon: helvine, genthelvite, and danalite
Authors: Kingsbury Arthur W. G.
Published: December 2006

Helvine and genthelvite are recorded for the first time in Britain; of the former, three occurrences in Cornwall and one in Devon, and of the latter, one occurrence in Cornwall, are described. British danalite has hitherto been represented by two old specimens with the vague locality ‘Redruth’, Cornwall; occurrences at four Cornish localities are described, and a further Cornish locality is provided by two old specimens previously labelled as garnet. Partial chemical analyses for the helvine, genthelvite, and danalite specimens are presented; helvine and genthelvite occur in pyrometasomatic-hydrothermal deposits in metamorphosed calcareous sediments and, in one instance, in greenstone; danalite in hydrothermal deposits or lodes in metamorphosed greenstone; the parageneses of the three minerals are discussed.
Mineral Analysis and Analysts
Authors: Hey M. H.
Published: December 2006

The history of the chemical analysis of minerals is shortly reviewed. Following rapid developments between 1770 and 1810, few important changes took place for close on 130 years; new procedures led to simpler and more convenient separations but not, on the whole, to greater accuracy. The older analyses are, in general, neither worse nor better than modern ones, and analyses can only be assessed on internal evidence, if available, or on the reputation of the analyst.

The development of microchemical and colorimetric techniques in the last 40 years has resulted in a great reduction in the amount of material required for a mineral analysis; 5 to 20 mg is usually sufficient, and in favourable cases a complete analysis may be possible on less than I mg. Some modern instrumental methods are considered, and it is concluded that they cannot wholly replace the classical wet-chemical methods in their modern developments.

W. F. Hillebrand (1894) deplored the tendency of some petrologists to demand large numbers of very incomplete rock analyses, and his remarks are considered apposite today.
Hematophanite, a derivative of the perovskite structure
Authors: Rouse R. C.
Published: December 2006

Hematophanite, ideally Pb4Fe3O8Cl, is tetragonal, space group P4mm, with a = 3·92 and c = 15·31 Å. The crystal structure, which has been refined to an R-factor of 9·1 %, may be described as an interlayering of perovskite-like units with a cesium chloride or, alternatively, a nadoritelike unit. The nadorite-like part consists of a double layer of PbO4Cl4 distorted square antiprisms. Iron atoms are in 6-fold (tetragonal bipyramidal) and 5-fold (square pyramidal) coordination.
Spherically arranged inclusions in post-tectonic garnet porphyroblasts
Authors: Harvey P. K. , Ferguson C. C.
Published: December 2006

Garnet porphyroblasts, containing elongate ilmenite inclusions arranged in an essentially spherical pattern, are described. The garnets are post-tectonic, and the inclusion pattern is the result of deformation and simultaneous replacement of the matrix by the growing porphyroblast.
The origin and petrogenetic significance of hour-glass zoning in titaniferous clinopyroxenes
Authors: Wass Suzanne Y.
Published: December 2006

Tertiary alkali basaltic rocks from the Southern Highlands, New South Wales, contain two types of clinopyroxene crystals, which exhibit excellent morphological development of hour-glass zoning. These are small, quench clinopyroxene crystals and large, abundant, euhedral phenocrysts. Electron microprobe analyses show that the different zone sectors derive from compositional differences, with variation in TiO2and Al2O3contents inversely with SiO2content being most significant. Increased depth of colour of titanaugites depends on increased coupled substitution of Al for Si in tetrahedral sites and of Ti3−in anM1site, while pleochroism is enhanced by increasing Fe content. It is suggested that the formation of hour-glass zoning is determined by an environment of crystallization where initial crystal growth is rapid relative to ionic diffusion in the melt, resulting in different chemistry for different growth directions within the crystal. This implies that, under certain conditions, kinetic factors, as well as the chemical composition of the host magma, may be significant in determining the chemical composition of phases precipitated, particularly where more than one crystallographic direction of growth is possible.
The thermal transformation of datolite, CaBSiO4(OH), to boron-melilite
Authors: Tarney J. , Nicol A. W. , Marriner Giselle F.
Published: December 2006

A kinetic and X-ray study of the dehydroxylation of datolite, CaBSiO4(OH), has shown that the decomposition occurs very rapidly above 700°C in air, with an activation energy for the reaction of the order of 200 kcal mole −1. The transformation is topotactic, the dehydroxylated phase being tetragonal with a 7·14 Å, c 4·82 Å, and particularly well formed even at the lowest temperatures of decomposition. Single-crystal studies have shown that two orientations of the new phase exist and that the original a of datolite becomes the unique axis of the tetragonal phase while the tetragonal a axes are oriented either parallel to or at 45° to the b and c axes of datolite. The new phase appears to be a boron-containing analogue of the melilite structure, composition Ca2SiB2O7, but is metastable. The basic sheet structure is preserved during the transformation but a reorganization of the tetrahedral layer from the 4- and 8-membered rings of datolite to the 5-membered rings of the new phase is involved, together with effective removal of protons and some silicon. The transformation can be explained in terms of an inhomogeneous reaction mechanism involving migration of calcium and boron into the new phase domains and counter-migration of silicon and protons, but with only minor readjustment of oxygens. The high activation energy of the reaction is explicable in terms either of the effort necessary to remove silicon from the domains of the new phase or of the difficulty of moving the large calcium ions through a relatively close-packed structure.
The crystal structure of julgoldite
Authors: Allmann Rudolf , Donnay Gabrielle
Published: December 2006

The structure of julgoldite, , has been determined and refined to an R value of 4·6 % based on 2417 symmetry-independent reflections, of which 765 are unobserved (weighted R = 4·3 %). The cell dimensions are a 8·922(4), b 6·081(3), c 19·432(9) Å, β 97·60(6)°, the space group is A2/m with Z = 4 and Dcalc 3·56 g cm-3. Julgoldite is isostructural with pumpellyite; the Si-O and Ca-O distances of julgoldite are identical, within experimental accuracy, with corresponding distances in pumpellyite; the Fe-O distances of julgoldite are about 0·09 Å longer than the corresponding (Al, Mg)-O distances in pumpellyite. The four hydroxyl groups and the extent of O-for-OH substitution are identified by valence-sum calculations.
An unusual clinopyroxene with complex lamellar intergrowths from an eclogite in the Sunndal-Grubse ultramafic mass, Almklovdalen, Nordfjord, Norway
Authors: Lappin M. A.
Published: December 2006

Clinopyroxene crystals with complex lamellar intergrowths of orthopyroxene and garnet are described. The orthopyroxene lamellae are irrationally orientated within the clinopyroxene host although the optical relationships of these minerals are consistent with (100) exsolution in clinopyroxene. The intergrowth is nevertheless considered to be the result of exsolution processes. Possible modes of origin are reviewed together with the general significance of exsolved pyroxenes in eclogite- and granulite-facies associations.
Possible origins of α-damage in diamonds from kimberlite and alluvial sources
Authors: Vance E. R. , Harris J. W. , Milledge H. J.
Published: December 2006

Heating experiments provide strong evidence that the transparent green coats on some diamonds from each of many localities are caused by α-particle irradiation after kimberlite injection and subsequent cooling. The natural diamonds with more or less homogeneous transparent green coats, studied in this work, appear to have received doses of at least 5 × 1013−1 × 1014 α.cm−2. For Pre-Cambrian kimberlites, such doses could occur if certain regions of the diatremes contained ⩾20 ppm by weight of equivalent uranium, after kimberlite injection and solidification.

Such considerations lead to the prediction that the radioelement concentrations in the Finsch kimberlite diatreme and the Bellsbank fissure kimberlite are considerably greater than those in the Premier mine, though radioelement segregation could produce the required local concentrations. Some exploratory autoradiographic measurements made on two kimberlite rock samples from Premier and De Beers Mines indicated that the radioelements were apparently distributed on a submicron scale, which would be a necessary, but not sufficient, condition for uniform α-irradiation of diamonds.

Diamonds from various alluvial sources showing green and brown spots arising from much heavier and more localized radiation damage are also discussed.