bluuebunny/crossref_metadata_2025 huggingface dataset:
A re-examination of cliftonite
Authors: Hey Max H.
Published: December 2006

Cliftonite was described by Sir Lazarus Fletcher in 1887 as ‘a cubic form of graphitic carbon’. He put forward reasons for regarding it as a new allotropic modification of carbon and other reasons suggesting that it is a pseudomorph of graphite after some cubic mineral, perhaps diamond, but did not definitely favour either view. On the evidence available hitherto, both suggestions were clearly possible.
Zoned olivines and their petrogenetic significance
Authors: Tomkeieff S. I.
Published: December 2006

The object of this paper is to demonstrate the widespread occurrence of zoned olivines in igneous rocks, to show that the zoning is continuous, that the composition varies from a magnesium-rich centre to an iron-enriched margin, and that these findings have an important bearing on the question of petrogenesis.

I propose to express the composition of olivine by stating only the percentage of fayalite, as the rock-forming olivines belong mainly to the forsterite-fayalite series. There are, however, a number of names in use for the members of this series. Assuming that the two names forsterite and fayalite are insufficient for the needs of classification, it yet seems to me that all but four of the existing names are superfluous.
Prismatic cleavage and steep rhombohedral form in α-quartz
Authors: Drugman Julien
Published: December 2006

As is well known, quartz rarely shows well-defined cleavages. Kenngott has shown that quartz that has suddenly been cooled, after strong heating, has a tendency to break up in the directions of rhombohedron faces. Breithaupt (cf. Hintze, Min., 1904, vol. 1, p. 1273) mentions ‘cleavage following the primary rhombohedron and the prism, rarely well defined, often passing into conchoidal fracture’.

It may be useful to put on record an example of clear rock-crystal in which cleavage is developed in all three 60° directions of the prism faces. The specimen was originally in the Daimeries collection, in Brussels, having been bought years ago at Idar, near Oberstein on the Nahe, by A. Daimeries. I obtained it from Mr. A. G. F. Gregory, who had bought the Daimeries collection. The locality from which it came is, unfortunately, unknown.
The crystallography of sartorite
Authors: Bannister F. A. , Pabst Adolf , Vaux George
Published: December 2006

Sartorite is one of four minerals once thought to be isomorphous. Of these only two are truly so—chalcostibite, copper antimony sulphide, CuSbS2; and emplectite, copper bismuth sulphide, CuBiS2—both orthorhombic minerals. The third, zinckenite, has been shown by two of the authors to be hexagonal and to approach more closely the formula Pb6Sb14S27 ═ 6PbS.7Sb2S3 than PbSb2S4 ═ PbS.Sb2S3. It seemed appropriate to continue a study of the series by an X-ray investigation of sartorite, a lead arsenic sulphide formerly supposed isomorphous with zinckenite. More than usual interest was attached to such a task, since discrepant interpretations of the symmetry and setting of sartorite had been obtained by well-known crystallographers.

Indeed, the difficulties of indexing different crystals of sartorite on the same lattice proved insuperable to G. F. H. Smith and R. H. Solly, so that they devised three incongruent lattices—one monoclinie and two anorthic. Also they used slightly different elements for each crystal. Their device, however, was not uniformly successful with certain crystals of sartorite previously measured by C. O. Trechmann. Two crystals in particular eluded their efforts. These, they decided, could not belong to the same species, but must be another mineral, perhaps a dimorphous form of sartorite, which they then named sartorite-α.
The relation of stellerite and epidesmine to stilbite
Authors: Pabst Adolf
Published: December 2006

The recent finding of a stellerite-like mineral in California has led to this study of its relations to epidesmine and stilbite. The mineral was found by Mr. Allen Nichol, mineralogist of the Division of Highways, in the quarry of the Calavera Materials Company near Oceanside, San Diego County. Some specimens reached the writer through the State Division of Mines. The mineral occurs as sheaf-like clusters of small glistening white crystals in cracks and cavities of andesite. The largest crystals are nearly a quarter of an inch long, but tend to aggregate formation so that they do not lend themselves to accurate goniometric measurement. They are apparently orthorhombic, of tabular habit, showing the three pinakoids and small bright faces of a pyramid. The excellent pinakoid cleavage has a pearly lustre, and if this is taken as (010) the crystals, which show parallel extinction, have the same optical orientation as stellerite.
The Huckitta meteorite, Central Australia (With Plates XII-XV.)
Authors: Madigan C. T.
Published: December 2006

The author arrived at Huckitta station, 135 miles north-east of Alice Springs, towards the end of June, 1937, on an expedition to the Tarlton Range at the north end of the Simpson Desert. The manager of the station, Mr. W. Madrill, said that a haft-caste named Mick Laughton employed on the station had a stone he would like to show, and this was produced by Laughton in the usual diffident manner of the half-caste. It proved to be a flat, rusty mass weighing a little over nine pounds. A few knocks with a hammer soon showed it to consist in part at least of malleable iron, and a meteorite was at once suggested. The specimen was not very closely examined, and the olivines, which show up so excellently on the polished surfaces, were entirely overlooked, which is quite easily done in the case of the iron-shale or the more weathered natural surface of the meteorite, although olivine makes up more than half the volume. It was said that the specimen came off a big stone which stood several feet out of the ground.
An eyepiece micro-planimeter
Authors: Cooke H. B. S.
Published: December 2006

Occasion arose recently when the writer required to make a number of comparative areal measurements of irregularly shaped portions of fossil corals in thin section, and it was found that the micrometric methods available were very tedious and involved considerable strain. A micro-planinmter has now been designed by means of which fairly accurate determinations of areas can be made with a minimum of eye strain. Though intended primarily for use with the petrographical microscope with the rotating stage, it can be adapted for use on microscopes of the fixed stage type.
On the presentation of chemical analyses of minerals
Authors: Hey M. H.
Published: December 2006

The results of a chemical analysis of a mineral are always presented, in the first place, as percentages of elements or oxides present, and until recently the only possible further treatment of these values was to calculate atomic or molecular ratios, group them according to accepted isomorphous groups, and deduce (if possible) an integral chemical formula. The degree of approximation to integral ratios accepted as satisfactory is, of course, quite arbitrary, and a decision as to the degree of complication acceptable in a chemical fornmla has often had to rest on very inadequate evidence. Some workers prefer to adjust the final ratios to show the errors evenly distributed, a procedure which has no real advantages.
Crystal-structure of a natural nickel-iron alloy
Authors: Owen E. A. , Burns B. D.
Published: December 2006

Natural nickel-iron alloys have been found in several places on the earth's surface. In addition to alloys containing a low percentage of nickel (about 3%), there are others which contain much higher percentages of nickel (about 70%). To alloys of the latter group the name awaruite is now generally given and it may include josephinite, souesite, and other alloys possessing high nickel content so long as they belong to the same phase and possess identical crystal-structures.

It is of interest to the mineralogist to know whether these alloys conform to the structure of nickel-iron alloys prepared in the laboratory and whether they fit into the accepted phase diagram of the nickel-iron system. It is of interest also to the physicist and the metallurgist to obtain information concerning these natural alloys, because some nickel-iron alloys made in the laboratory are difficult to prepare in a state of true equilibrium. Data derived from the study of the natural alloys may help to throw light upon the structure of these artificial alloys.
Crystallography of aramayoite
Authors: Berman Harry , Wolfe C. W.
Published: December 2006

The original description of aramayoite by Spencer in 1926 contained only a qualitative discussion of the crystallography, because suitable crystals for a more rigorous treatment were not found. The pseudo-tetragonal symmetry was recognized, and cleavages were noted, but only one was defined. Twinning was later observed in polished section by Schneiderhöhn and Ramdohr, but undefined. Yardley demonstrated the triclinic symmetry of aramayoite by the Laue method, and determined the spacings of a considerable number of planes in the crystal. From these data she formulated a unit cell and correlated the X-ray data with Spencer's crystallographic results.

Several specimens of aramayoite found in our recently acquired Ahlfeld Bolivian collection contained small but excellent crystals. Measurement of these indicated that the Yardley X-ray crystallography was not consistent with an adequate morphological treatment of the form-development. The twenty-seven forms found by us lead to an obvious crystallographic unit (fig. 1), bearing a rather complex relationship to the Yardley unit. In order to test the suitability of the latter, we repeated the X-ray examination by the modern Weissenberg method and found complete accordance with our morphological treatment, as will be shown below.
The existence of reversible photosensitivity in some artificial materials containing rutile
Authors: Williamson W. O.
Published: December 2006

In 1934 a contribution from America (Parmelee and Badger, p. 2) reported that a certain glaze, containing rutile, showed rapid reversible darkening in daylight. It was stated that C. H. Zwermann, Jr., ascribed this photosensitivity to titanium. In the present author's experience the phenomenon is often exhibited, in varying degrees, by commercial glazes based on rutile or on the purified titanium dioxide available in industry, as well as by glazes made up in the laboratory from chemical titanium dioxide of high purity. Lee, also in America, observed reversible darkening in sunlight in commercial titanium dioxide itself, and the existence of this effect was confirmed by Williamson (1937) for some brands of commercial titanium dioxide available in Britain. These brands were affected by daylight which had passed through glass, and some tentative suggestions were made regarding the mechanism of the reversible darkening. Later it was demonstrated (Williamson, 1939) that reversible darkening in daylight could be produced in a sample of titanium dioxide of considerable purity, which was itself not discoloured by light, by contamination with iron according to a special method.
Iron-rich kornerupine from Port Shepstone, Natal
Authors: de Villiers J. E.
Published: December 2006

A very interesting kornerupine-bearing rock was sent by Mr. W. H. Cross during 1938 to the Geological Survey for identification. The material, of which about 800 grams were available for study, was stated to have been found in the Port Shepstone district. The occurrence has, however, not been visited by the writer.

The hand-specimens examined were all somewhat weathered. Macroscopically these consisted of an intergrowth of grey, columnar crystals of kornerupine, up to 5 centimetres in length, and adhering iron-stained quartz. Shiny ‘books’ of biotite occur both in the kornerupine and the quartz, while small patches and specks of dark brown tourmaline and bluish grandidierite were observed enclosed in the kornerupine.
Studies of mineral sulpho-salts: II. Jamesonite from Cornwall and Bolivia (With Plates XXVI and XXVII.)
Authors: Berry L. G.
Published: December 2006

Jamesonite is described in Dana (1892, p. 122) as a soft, brittle, steel-grey to lead-grey mineral forming acicular orthorhombic crystals, a: b = ‘0·915:1’ (in error for 0·8195:1), with perfect basal cleavage; composition, 2PbS.Sb2S3; principal occurrence, Cornwall. Jamesonite is taken as the type member of a group that includes cosalite, described in the first of these studies (1939), dufrenoysite, and other minerals of analogous composition.
Hydrozincite from Narlarla, West Kimberley district, Western Australia
Authors: Prider Rex T.
Published: December 2006

Hintze (1930) has pointed out the considerable variation in analyses of hydrozincite and the various formulae assigned to this mineral. Further data concerning this comparativeIy rare mineral are therefore desirable. Hydrozincite has been found at Narlarla, Western Australia, and this material is described below.

Narlarla is situated in the Napier Range, West Kimberley district (long. 124° 43′ E., lat. 17° 16′ S.), 75 miles due east from Derby, on the south side of the Barker River gorge (fig. 1). Several small silver-lead-zinc ore-deposits occur in the hills at Narlarla which are made up entirely of Devonian limestone. The occurrences have been described by Woodward (1907, p. 11), who, in his report, gives the results of assays of several specimens of the ore. These occurrences are Unique as they are the only known post pre-Cambrian primary ore-deposits in Western Australia. (Secondary gold deposits occur in the Donnybrook sandstone which is considered to be probably of Permian age (Forman, 1936).) The unique character of the Narlarla deposits has been noted by Simpson (1939, p. 218), who, however, offers no explanation as to their genesis. The absence of any post-Devonian igneous intrusives, other than the leucite-lamproite plugs (Wade and Prider, 1940) which are intrusive into the Permian rocks of the Fitzroy River area to the south of Narlarla, seems to indicate that these deposits are genetically related to the lamproite magma. The nearest known occurrence of the leucite-lamproites is at Mr. North, some 15 miles to the south (fig. 1), but there may be closer occurrences as the area has not been very closely examined, and the widespread distribution of the lamproite magma has been demonstrated (Wade and Prider, 1940).
Dravite-bearing rocks from Dinas Head, Cornwall
Authors: Agrell S. O.
Published: December 2006

In a previous paper describing the geological and petrographical details of the adinoles of Dinas Head, short references were made to the common occurrence among the adinoles and associated rock-types of the magnesia-rich tourmaline, dravite. It is proposed now to describe these tourmaline-rich rocks in more detail and to discuss the question of their origin.

Adinoles with accessory tourmaline occur wherever true adinoles are developed at Dinas Head, although tourmaline is characteristically absent from types 2 a, b, c, and 3 [1, pp. 318–323]. Bands with up to 30 % tourmaline occur interbanded with normal adinoles of type 1 and with certain spilosites.
Native gold and silver with other minerals from the Old West mine, Penhalonga, Southern Rhodesia (With Plate III.)
Authors: Macgregor A. M.
Published: December 2006

Large specimens of native gold showing crystalline form are not at all common in Southern Rhodesia, but the recently discovered gold with adherent silver from the Old West mine, Penhalonga, would be outstanding wherever it had been found.

About the middle of December 1940, Mr. D. V. Burnett, Director and Consulting Engineer to the Rezende Mines Limited, the owners of the property, lent two specimens to the Geological Survey for examination. The following week Mr. B. Lightfoot, Director of the Southern Rhodesia Geological Survey, visited the mine and examined the cavity where the specimens had been found. He made notes and collected specimens of the associated minerals, and borrowed a few other specimens which had been retained at the mine.
On a crystal of augelite from California
Authors: Peacock M. A. , Moddle D. A.
Published: December 2006

Augelite was originally described from Sweden by Blomstrand (1868) who obtained the composition 2Al2O3.P2O5.3H2O from a massive mineral with cleavage in three directions. No further description of this inadequately defined mineral appeared until Prior and Spencer (1895) gave their complete and exact characterization of well-crystallized material from Machacamarca, department Potosi, Bolivia, supplemented by observations by Spencer (1898, 1907) on further finds at Tatasi, department Potosi, and at Oruro, Bolivia.

Lemmon (1935) first recognized augelite as cleavage masses in the commercial deposit of andalusite at White Mountain, Mono County, California, and gave determinative observations which established the identity of the mineral. In this locality Kerr (1932) had noted corundum, diaspore, pyrophyllite, alunite, lazulite, and rutile, associated with the andalusite. In addition to these minerals Professor Joseph Murdoch of the University of California at Los Angeles, has found small, white, tabular crystals of apatite in a specimen carrying augelite. Crystals of augelite from this deposit, with a number of new forms, were mentioned by Pough (1936) in an inconspicuous notice which we did not see until our work was nearly done.
The determination of the orientation of section planes of meteoritic irons
Authors: Hey Max H.
Published: December 2006

The Widmanstetter figures on a general plane section of a meteoritic iron of the octahedrite class consist of kamacite bands running in four directions, the traces of the four planes of the octahedron, while tessellated octahedrites show three more sets of bands, the traces of the cube planes. The angles which these bands make with one another give data which are in principle sufficient to define the crystallographic axes of the iron, but in practice there does not appear to be any simple direct method of effecting this definition. In the following, two simpler cases are first discussed, followed by a method for the general case somewhat shorter than any published method I am aware of, and by methods for orientation from the Neumann lines and from inclusions.
A suite of volcanic rocks from south-west Uganda containing kalsilite (a polymorph of KAlSiO4)
Authors: Holmes Arthur
Published: December 2006

During the last few years large collections of rock specimens from the Toro-Ankole volcanic fields, east and south-east of Ruwenzori, have been sent to Durham by the Geological Survey of Uganda for petrological investigation. The specimens recently studied include representatives of a suite of highly potassic ultrabasic lavas. Some of these resemble melanocratic olivine-nephelinites or olivine-rich ankaratrites, but the nepheline-like felspathoid which they contain, instead of being nepheline, is a polymorph of KAlSiO4. For chemical reasons this mineral was at first thought to be kaliophilite. Other types, closely related, contain leucite, biotite, or melilite, in addition to the supposed kaliophilite.
Merwinite as an artificial mineral
Authors: Phemister James , Nurse R. W. , Bannister F. A.
Published: December 2006

In the investigation of the system CaO–MgO–SiO2 by Ferguson and Merwin the orthositicate 3CaO.MgO.2SiO2 was not observed, and the existence of this compound was first proved in 1921 by Larsen and Foshag who detected it in a contact-altered limestone at Crestmore, California, and gave to it the name merwinite. Since then this compound has been found in contact-altered limestones at Scawt Hill, Antrim, near Neihart in the Little Belt Mts. of Montana, and at Velardeña, Mexico. The history of the recognition of merwinite as an artificial mineral is less easy to trace, but it seems that research workers on refractory bricks were the first to recognize its existence. Thus U.S.A. Patents applied for in the years 1934 and 1935 and British Patents applied for on 11.10.1935 and 19.5.1936 by Non-Metallic Minerals Inc. specify merwinite and periclase as the essential constituents of a refractory brick produced by firing mixtures of dolomite and serpentine, dolomite and sand, or impure magnesite and dolomite at temperatures varying between 2700° and 2900° F.
Chemical data on a silica-poor argillaceous hornfels and its constituent minerals
Authors: Stewart F. H.
Published: December 2006

The hornfels discussed here was collected from Sparcraigs, near Whitecairns, eight miles to the north of Aberdeen, very close to the eastern contact of the basic igneous intrusion of Belhelvie. The Highland Schists of the district are very poorly exposed, but at this locality there are a few small isolated outcrops of high-grade hornfels, nearly all silica-poor types, with garnet, spinel, hypersthene, cordierite, plagioclase, and biotite as their chief mineral constituents. The actual contact is obscured, but the igneous rock, an olivine-gabbro, is exposed at about twenty yards from the hornfels.
The mica of certain coal-measure shales in South Wales
Authors: Nagelschmidt G. , Hicks D.
Published: December 2006

During a study of the sources of the dusts in South Wales coal mines, carried out on behalf of the Industrial Pulmonary Disease Committee of the Medical Research Council, a mineral of the mica group was found as the main constituent of the shales overlying the coal in several mines. Of six shales investigated four were associated with anthracite, one with semi-bituminous, and one with bituminous coal. Between the coal seam itself and the shale which forms its roof there usually occurs a more coaly shale referred to locally as ‘clod’. Five of the samples investigated were isolated from ‘clods’ and one from a roof.
The forgotten uses of selenite
Authors: Bromehead C. E. N.
Published: December 2006

We are apt to regard selenite or transparent gypsum as a useless mineral, apart from the very small quantity used in plates for microscope work. It is the object of this paper to show that from the first, to at any rate the seventeenth century in Europe and to the first half of the nineteenth in South America, considerable use was made of it. For the classical period the argument is based upon the identification of lapis specularis as mainly, if not entirely, selenite. Most translators render the name as talc or mica, the first word probably a vulgar error for the second, while some admit gypsum to have been included; Bailey in his notes on Pliny considers that two passages suggest gypsum but gives the preference to mica, while Zeitler claims nearly all the passages referred to below for this mineral. Pliny is, of course, our chief authority: I give the relevant passages in Philemon Holland's translation as more in keeping with the greater part of this paper, adding notes and the original Latin where necessary.
A geochemical study of Lewisian metasedimentary granulites and gneisses in the Scourie-Laxford area of the north-west Scotland
Authors: Okeke P. O. , Borley G. D. , Watson J.
Published: December 2006

Major element, trace element, and REE data for metasedimentary granulites and their retrogressed derivatives formed from Archaean parent-rocks at two localities in the Lewisian complex of north-west Scotland are presented.

The metasedimentary rocks are enclosed in and intruded by metatonalites and related calc-alkaline rocks and have been highly deformed and metamorphosed along with these rocks. They are geochemically distinct from this meta-igneous suite and range from highly aluminous to highly siliceous types. Comparisons of major and trace element data with those for unmetamorphosed Archaean and post-Archaean sediments suggest that they are derived from a detrital shale-greywacke assemblage, which may have included a volcaniclastic component. High ΣREE and ΣLREE suggest that the source-rocks included fractionated felsic igneous rocks.

Evidence that depletion in the large ion lithophile elements K, Rb, Th accompanied high-pressure granulite metamorphism supports the view, based on data derived from the associated meta-igneous rocks, that depletion was effected by active fluids rather than by abstraction of a partial melt and suggests that removal of K and Th began only when a considerable reduction of Rb had taken place.
Clay minerals in the basalts of the South Pennines
Authors: Walters S. G. , Ineson P. R.
Published: December 2006

X-ray diffraction, electron microprobe and STEM EDAX analyses of basalts from the South Pennines (Derbyshire) indicate that Fe-rich smectites are the dominant alteration products, occurring either as pseudomorphs or infilling veins and vesicles. Previously chlorite has been identified as the common alteration product but its occurrence is very infrequent.
Vertical chemical gradients in a single grain of magnetite from the Bushveld Complex, South Africa
Authors: Grant Cawthorn R. , Mccarthy T. S. , Davies G.
Published: December 2006

Very large crystals of magnetite, up to 2 cm, are found in pure magnetitite layers in the upper zone of the Bushveld Complex. Detailed electron microprobe analysis of one of these indicates a vertical compositional zoning of Cr (a highly compatible element in magnetite) quite different from the concentric zonation often found, for example, in feldspars in intrusive rocks. It is shown that these crystals could not have grown to their present size in suspension in the magma chamber. Annealing of many small crystals into a single grain could occur either by the Ostwald ripening process at temperatures close to the liquidus or by subsolidus recrystallization. Alternatively, these grains could have formeddirectlyfrom the magma by upward growth from the floor of the magma chamber, by a process analogous to crescumulate or heteradcumulate growth but in the absence of other crystallizing phases. All of these models require the observed Cr gradient to be produced during the initial crystallization event and not as a secondary effect.
Gortdrumite, a new sulphide mineral containing copper and mercury, from Ireland
Authors: Steed G. M.
Published: December 2006

Gortdrumite superficially resembles chalcocite but is more distinctly anisotropic, and is present in a vein containing ferroan dolomite and baryte which cuts dolomitized limestones from the Gortdrum Orebody of County Tipperary, Ireland. It has an empirical formula of approximately (Cu,Fe)6Hg2S5. A distinctive powder diffraction X-ray pattern has been obtained which indicates a probable orthorhombic crystal lattice with a 14.96, b 7.90, and c 24.1 Å. The reflectivity at 589 nm is 25.1 to 27.9% and the VHN10 hardness range 186 to 230.
Wilcoxite and lannonite, two new fluosulphates from catron county, New Mexico
Authors: Williams S. A. , Cesbron F. P.
Published: December 2006

Both Species were Found as post-Mine Minerals in the Lone Pine mine, Catron County, New Mexico. They occur encrusting ores of fluorite-pyrite with khademite and gypsum.

Wilcoxite is clear, colourless to white, H = 2, D = 1.58. Abundant as spongy masses of perfect to somewhat rounded crystals. Stubby prisms are bounded by {100}, {010}, {110}, {10}, and {01}. Triclinic P or P1 with a = 14.90, b = 6.65, c = 6.77 Å, α = 117° 26′, β = 100° 35′, γ = 80° 10′, and Z = 1. Strongest lines are 5.654(9) 110, 11, 4.908(10) 11, 4.371(6) 201, 210, and 3.384(5) 11, 111. Biaxial negative with α = 1.424, β = 1.436, γ = 1.438, 2Vα = 48°. Analysis gave MgO 6.61%, Al2O3 8.13, Fe2O3 0.46, MnO 0.13, SO3 27.50, H2O 56.40, F 3.48, total 101.24 (corr. for O ≡ F) leading to MgAl(SO4)2F·18H2O.

Lannonite is usually as chalky white aggregates of microscopic tetragonal (square) platelets; H = 2, D = 2.22. Indexed as tetragonal a = 6.84, c = 28.01 Å, and Z = 1. Strongest lines are 13.98(10) 002, 4.840(7) 110, 3.980(5) 116, and 3.456(7) 017. Uniaxial positive with ω = 1.460 and ε = 1.478. Analysis gave CaO 12.06%, MgO 4.46, Al2O3 11.06, SO3 34.40, H2O 32.00, F 9.44, total 99.45 (corr. for O ≡ F) leading to HCa4Mg2Al4 (SO4)8F9·32H2O.

Both minerals and mineral names have been approved by the Commission on New Minerals and New Mineral Names, IMA.

New analytical data for the khademite associated with these species are presented.
Fluocerite and its alteration products from the Afu Hills, Nigeria
Authors: Styles M. T. , Young B. R.
Published: December 2006

Eluvial pebbles from the Afu Hills, Nigeria, are largely composed of fluocerite, Ce0.50La0.28Nd0.11 Pr0.04Th0.03Ca0.02F3, with minor monazite. The fluocerite shows two types of alteration, to bastnäsite, and to bastnäsite-(La) with cerianite. Electron microprobe analyses are given for fluocerite, monazite, bastnäsite and bastnäsite-(La). The refined cell parameters of the fluocerite are a = 7.130±0.001, c = 7.2985 ± 0.001 Å. Strongest lines are 3.204 Å (100), 3.65 (45), 2.059 (45), 2.010 (45) and 3.565 (40). Space group P 63/mcm, Z = 6, Dcalc. = 6.12 g cm−3, ω = 1.613, ε = 1.609 both ±0.002, uniaxial negative. For bastnäsite a = 7.131 ± 0.002, c = 9.786±0.004 Å, for cerianite a = 5.460 ± 0.005 Å.
Occurrence of thaumasite in a seawater-basalt interaction, mururoa atoll (French Polynesia, South Pacific)
Authors: Noack Y.
Published: December 2006

The first occurrence of thaumasite resulting from seawater-basalt interaction has been discovered in a drill hole on Mururoa atoll (French Polynesia, South Pacific). This sulphate-carbonate-silicate is associated with zeolites (phillipsite, chabazite, gmelinite), apophyllite, analcime, and gyrolite. In this environment thaumasite can be considered as the last mineral of an alteration sequence. It crystallized from a Ca-SO3-CO2-rich and Al-Na-K-poor fluid. The temperature of this solution is unknown, but was probably not greater than 100°C.
Incommensurate superlattice ordering in priderite
Authors: Pring A. , Jefferson D. A.
Published: December 2006

The mineral priderite has been examined by electron microprobe analysis and electron diffraction. The composition was approximately (K0.97Ba0.33)(Fe1.17Ti6.60Mg0.23)O16, which is in line with the observed superlattice periodicity of m = 5.88, there being inter-growths of m = 5 and m = 6 superstructures. A surprisingly high degree of lateral correlation between tunnel cations was noted.
The aqueous chemistry of uranium minerals. 4. Schröckingerite, grimselite, and related alkali uranyl carbonates
Authors: O'Brien Timothy J. , Williams Peter A.
Published: December 2006

Using solution techniques, ΔG°f(298.2k) has been calculated for schröckingerite, NaCa3UO2(CO3)3 SO4F · 10H2O, and grimselite, NaK3UO2(CO3)3 · H2O. The values are −8077.3 ±8.7 and −4051.3 ±1.8 kJ mol−1 respectively. ΔH°f(298.2k) for grimselite is −4359.0 ± 1.8 kJ mol−1. An estimate for ΔG°f of the synthetic compound Na4UO2(CO3)3(s) using previously published equilibria has been made, −3720.0±9.7 kJ mol−1. The results have been used to reconstruct the chemical environments in which these and related compounds can form. Grimselite is only stable at relatively high activities of K(aq)+ and the alkali metal carbonates containing only potassium or sodium ions have not been reported to occur naturally. This is most probably due to their relatively high solubility in water. Schröckingerite can form from solutions which are more than saturated with respect to calcite and fluorite. The close relationship of schröckingerite with gypsum, observed frequently in the field, is evident from synthetic and solution studies.
Petrology of alkali wehrlite sills in the Oman Mountains
Authors: Lippard S. J.
Published: December 2006

Alkaline mafic sills of Jurassic to Cretaceous age in the Oman Mountains have coarse-grained wehrlite centres composed of olivine and zoned diopside-titanaugite with large interstitial poikilitic titanian hornblendes and titanian barian phlogopites and biotites which appear to have crystallized from a trapped, intergranular, volatile-rich liquid. The fine-grained chilled margins of the sills are olivine-poor and composed largely of titanaugite, kaersutite, sphene, and interstitial altered plagioclase. The rocks have high contents of incompatible elements (Ti, P, Sr, Ba, Zr, Nb, and others) and steeply inclined, light element enriched, REE patterns. The parent magma is estimated to have been a hydrous alkali picrite with c. 12% MgO from which the wehrlite formed by olivine accumulation. The unusual tectonic setting of the sills, in a Mesozoic continental margin sequence emplaced in an Alpine thrust belt, is noted.
Malayaite and tin-bearing garnet from a skarn at Gumble, NSW, Australia
Authors: Mulholland I. R.
Published: December 2006

Malayaite and tin-bearing garnet occur within a skarn assemblage at Gumble, NSW. A metasomatic origin is proposed for these minerals under conditions of T = 300-500°C Xco2 < 0.30 and fO2 = 10−18 to 10−30 bars. Malayaite has formed as a result of reaction between a metasomatic fluid rich in Sn, F, H2O and silica, and tin-bearing andradite and wollastonite. The main requirements for tin-bearing skarn formation appear to be an F-Sn-rich granite, an iron-rich skarn assemblage, and a relatively long cooling history.
Subcalcic, Fe-rich amphiboles in meta-dolerites, Glenrock Station, NSW, Australia
Authors: Offler R.
Published: December 2006

Sub-greenschist facies metamorphism has produced unusual subcalcic, Fe-rich actinolitic amphiboles in meta-dolerites from the Glenrock Station area, NSW. They show edenite, riebeckite, ferri-tschermakite and Ti-tschermakite coupled substitutions. Their high Fe content is attributed to highaFe2+andaFe3+in the fluid phase produced during the breakdown of clinopyroxene, hornblende, magnetite, and ilmenite. The highaFe2+led to Fe led to Fe2-occupying theBsite, resulting in the formation of subcalcic amphiboles. Variation inaFe2+,aFe3+,aMg,aSi,aAl, andaCa, in different domains resulted in the crystallization of chemically inhomogeneous amphiboles.
Platy phlogopite from blast-furnace slags
Authors: Wearing E.
Published: December 2006

Phlogopite mica has crystallized from blast-furnace slags at atmospheric pressure. Its chemistry is characterized by an excess of Na and K over their normal stoichiometric content, which is attributed to a composite association between phlogopite and glass. The diffraction pattern indicates that the phlogopite has a preferred orientation around the a-axis. Scanning electron microscopy shows that this phlogopite consists of numerous small platelets, which probably have their a-axes aligned.
Sulphide mineralogy of the Tomnadashan copper deposit and the Corrie Buie lead veins, south Loch Tayside, Scotland
Authors: Pattrick R. A. D.
Published: December 2006

Copper mineralization at Tomnadashan is associated with granitic lenses intruded into a small Caledonian diorite body. The mineralization occurs as disseminations and irregular veinlets and mainly comprises pyrite, chalcopyrite, tetrahedrite-tennantite, calcite, and quartz. There are small inclusions of bismuthinite, galena, aikinite [(Cu,Pb,Fe,Bi)S3], and a mineral with a chemistry similar to hodrushite (Cu8Bi12S22). The tetrahedrite contains up to 6.1 wt. % bismuth.

Four km to the south, at Corrie Buie, are quartz veins, hosted by meta-limestones, containing galena with minor amounts of chalcopyrite, pyrrhotite, sphalerite, electrum, schirmerite, and lillianite homologues.

The mineralogy of both deposits is consistent with that associated with acid magmatism. There are mineralogical similarities between the two deposits but the style of mineralization at Tomnadashan suggests a limited hydrothermal system and therefore the Corrie Buie veins may be related to felsic intrusives to the south.
Celadonite-aluminous-glauconite: an example from the Lake District, UK
Authors: Loveland P. J. , Bendelow V. C.
Published: December 2006

An occurrence of a celadonite-like mineral in a weathered basalt in the Lake District has been investigated by X-ray diffraction, X-ray fluorescence, electron microprobe, and infra-red spectroscopic methods. The bulk composition of the mineral corresponds to an aluminous-glauconite. The data show that the mineral is most probably a celadonite-muscovite or celadonite-illite mixture, although a celadonite-phengite cannot be entirely discounted. Approximately 10% smectite layers are also present. The results suggest that re-examination of many aluminous glauconites may show them to be mixtures of this type.
Mineral chemistry of regional chloritoid assemblages in the Chlorite Zone, Lycian Nappes, South-west Turkey
Authors: Ashworth J. R. , Evirgen M. M.
Published: December 2006

In the Ören area at the base of the Lycian Nappes, chloritoid is common on a regional scale. Mn and inferred Fe3+contents are low. Chloritoid + quartz occur rather than the more hydrous equivalent pyrophyllite + chlorite, Fe/(Fe + Mg) values in chlorite ranging down to 0·27. Calcite and dolomite, which coexist with chloritoid and pyrophyllite, give a temperature estimate of 350± 30°C, implying moderate to high activities of water for pyrophyllite stability. Muscovite-paragonite geothermometry is unreliable. Mg/Fe distribution coefficients between chloritoid and chlorite differ systematically from literature values from higher grades (biotite and garnet zones). Intensity of colour in chloritoid correlates with inferred Fe3+content, which decreases outwards in grains showing prograde growth zoning.
Garnet websterites and associated ultramafic inclusions from a nepheline mugearite in the Walcha area, New South Wales, Australia
Authors: Stolz A. J.
Published: December 2006

A nepheline mugearite dyke in the Walcha area, New South Wales, contains xenoliths of Cr-diopside lherzolite, garnet- and spinel websterites, and two- pyroxene-garnet granulites. The Cr-diopside lherzolite xenoliths are regarded as refractory upper mantle which finally equilibrated at c. 950–980°C. The garnet websterites are considered to represent spinel websterite segregations from an Mg-rich olivine tholeiite magma at 14–16 kbar which on isobaric cooling to 1000–1050°C passed into the garnet pyroxenite stability field. Spinel-amphibole websterites which probably last equilibrated at c. 950°C and pressures of 9–12 kbar have dose mineralogical affinites with the Cr-diopside lherzolite xenoliths. The mafic granulites may represent metamorphosed crystal segregates resulting from relatively large degrees of crystallization of tholeiitic basaltic magma which finally equilibrated at c. 14 kbar and 1000°C Subcalcic clinopyroxene and spinel megacrysts crystallized from the host nepheline mugearite at c. 13–20 kbar.
Mineral chemistry of coexisting phases from shonkinitic rocks, Salem, Tamil Nadu, India
Authors: Friend C. R. L. , Janardhan A. S.
Published: December 2006

Gabbroic-textured shonkinitic rocks of unknown age cut deformed Archaean dunites and peridotites in the area immediately north of Salem. Magnesite formation post-dates their intrusion. The location of these rocks and the magnesite is thought to be controlled by the intersection of two major basement lineaments. A sequence of crystallization of the minerals and rocks from early undersaturated to late oversaturated rocks is established. Compositions of the coexisting mineral phases are reported here for the first time. Clinopyroxenes, which are relatively unevolved, commonly coexist with olivine (chrysolite) and sanidine. Bronzite, often intergrown with magnetite and green spinel, is occasionally present. In the most undersaturated rocks nepheline-sanidine fingerprint intergrowths occur, whilst perthitic sanidine, albitic plagioclase, and quartz are present in over-saturated rocks. Late in the crystallization sequence, in over-saturated rocks, PH2O appears to have increased allowing the formation of amphibole as well as clinopyroxene.
Zaisho—a pallasite containing pyroxene and phosphoran olivine
Authors: Buseck Peter R. , Clark Jim
Published: December 2006

The Zaisho meteorite, one of only four known pallasite falls, contains pyroxene, which is rare in pallasites, and it is only the fourth meteorite known to contain phosphoran olivine. Except for a recent report by Goodrich (1984) such olivine appears to be restricted to pallasites, and to those containing the rare Mg phosphate, farringtonite. It is unique among olivines in having P in tetrahedral sites and having vacancies, for charge balance, in octahedral sites. Zaisho also contains stanfieldite and a phosphate having a composition between that of stanfieldite and farringtonite. Its metallographic cooling rate is similar to that of many other pallasites, but its average olivine composition, Fa18.3, places it in a small group with more Fe-rich olivines than most pallasites.
Clay and pyrite transformations during ignition of pulverised coal
Authors: Hubbard F. H. , McGill R. J. , Dhir R. K . , Ellis M. S.
Published: December 2006

Clay minerals are the principal reactive, non-combustible, phases present in the pulverized coal burned in power station furnace units. Despite the short heating time involved, the clay mineral impurity is wholly transformed in the ignition.

Illitic clays are partially melted, fluxed by water and potash, to produce an alumino-silicate melt phase. The melt is frothed by the synchronous production of carbon dioxide in an iron oxide catalysed oxidation of associated carbonaceous matter. This produces the hollow, gasfilled, glass-walled spheres (cenospheres) characteristic of pulverized fuel ash (PFA). Partial, primary devitrification crystallization of mullite and quartz from the high-alumina glass is general and the extent of devitrification may influence the pozzolanic efficiency of the PFA cenospheres.

Without the advantage of potash fluxing, the kaolinite lattices are dehydrated and transformed, without melting, to amorphous aluminosilicate and crystalline mullite.

Oxidation of pyrite leads to coating of cenospheres by condensed magnetite and the emission of sulphur dioxide in the flue gases.
Primary baddeleyite (Zr02) in kimberlite from Benfontein, South Africa
Authors: Scatena-Wachel D. E. , Jones A. P.
Published: December 2006

Baddeleyite was found during an electron microprobe study of kimberlite from the Benfontein Sills, which are famous for their igneous carbonate and cumulus features. Based on its close textural association with both groundmass and cumulus oxides (spinels, ilmenite, perovskite), the baddeleyite appears to be primary and crystallized directly from the kimberlite magma. The baddeleyite is remarkably pure, with average ZrO2 and HfO2 of 96.4±1.3 and 1.72±0.08 wt. % respectively. Minor element ranges found were: TiO2 0.32–0.80, CaO 0.31–0.80, FeO 0.43–1.31, MgO 0.06–0.24, SiO2 0.04–0.19, Cr2O3 0–0.07, and Al2O3 0–0.10 wt.%. Several additional trace elements were sought (Ce, Cs, Mn, Nb, Nd, Sr, Y, Yb, and U) but were not detected.
Jeppeite, a new K-Ba-Fe titanate from Walgidee Hills, Western Australia
Authors: Pryce M. W. , Hodge L. C. , Criddle A. J.
Published: December 2006

Jeppeite, a new mineral, similar in composition to and overgrown on priderite, has been found in the lamproite plug of Walgidee Hills (18° 19′ S, 124° 51′ E), Western Australia. The mineral is named for the discoverer, Dr J. Jeppe. It is monoclinic, C2/m, a 15.453 b 3.8368 c 9.123 Å β 99.25°, strongest powder lines 4.50(002) (4), 3.07(310) (10), 2.99(003,31) (10), 2.961(20) (4), 2.812(311,112) (10), 2.091 (6), 2.074 (6), 1.919 (8) similar to artificial K2Ti6O13. The sparse eluvial crystals are black, elongated along b, bounded by {100}, {20} faces (Λ 45°) and {010}; perfect 100 and good 20 cleavages or partings, submetallic lustre, pale-brown streak, brittle, and cleave into (100) flakes. Dobs 3.94, Dcalc 3.98. Colour values for illuminant C from reflectance spectra for Rp, Rb, and Rθ are: Y% 13.3, 14.4, 16.6; λd 474, 473, 475; and Pe% 5.1, 4.5, 4.3. Refractive indices from reflectances at 590 nm in air are 2.13, 2.21 and 2.35. In thin section, αΛα10° blue, β = b dark greenish brown almost to black, γ = c brown. Bireflectance and birefringence positive. H 5–6, VHN100 orientation dependent; for indentations normal to b 664–773.

Jeppeite is common in the lamproite as prismatic to acicular aggregates associated with priderite, richterite, shcherbakovite, wadeite, perovskite, and apatite in a green and white celadonite and chlorite matrix, with a little calcite and sphene, after olivine, pyroxene, and leucite.

Electron probe analysis, using Fe, Ti, nepheline, and benitoite standards, gave K2O 8.47, BaO 17.35, TiO2 69.29, Fe2O3 (total Fe) 4.74, sum 99.85%; (Mg, Na, Zr detected). This analysis calculates to (K1.15,Ba0.73)Σ1.88 (Ti5.56, Fe3+0.38)Σ5.94O13, or ideally, (K,Ba)2(Ti,Fe)6O13.
Sweetite, a new mineral from Derbyshire
Authors: Clark A. M. , Fejer E. E. , Couper A. G. , Jones G. C.
Published: December 2006

Sweetite, naturally occurring Zn(OH)2 with tetragonal symmetry, has been found at Milltown, near Ashover, Derbyshire. It occurs as colourless or whitish bipyramids up to 1 mm in size scattered over the surface of colourless fluorite cubes. The cell dimensions are α 8,222 and c 14.34Å with Z = 20. The strongest lines of the X-ray powder pattern are (d, I, hkl): 4.53 37 (112); 3.572 60 (004,202,211); 2.922 100 (213,220); 2.708 18 (105,204); 2.257 17 (224,215,321); 1.840 11 (226,420,413); 1.764 24 (316). Sweetite is uniaxial negative, ω 1.635, ɛ 1.628. Dmeas is close to 3.33 and Dcalc 3.41. Chemical analysis gave 84.3% ZnO and 17.0% H2O, while theoretical figures for Zn(OH)2 are 81.9 and 18.1% respectively.
Straczekite, a new calcium barium potassium vanadate mineral from Wilson Springs, Arkansas
Authors: Evans Howard T. , Nord Gordon , Marinenko John , Milton Charles
Published: December 2006

Straczekite, a new calcium barium potassium vanadate from Wilson Springs (formerly Potash Sulfur Springs), Arkansas, occurs as a rare secondary mineral in fibrous seams in gangue. The dark greenish-black crystals are very soft, thin laths up to 0.5 mm in length, forming thick masses. No single-crystal X-ray patterns could be obtained, but good electron diffraction patterns yielded a monoclinic unit cell in space group C2/m, C2, or Cm. The cell parameters were refined by least squares analysis of Guinier-Hägg X-ray powder data: a 11.679(2), b 3.6608(4), c 10.636(2)Å, β = 100.53(4)° (strongest lines are: 003, 3.486, 100; 001, 10.449, 50; 020 1.8306, 50; 01/510, 1.9437, 15; 111/03, 3.255, 10; 311/12, 2.492, 10; 021, 1.8030, 10). Chemical analysis yields the formula: (Ca0.39Ba0.31K0.33Na0.11)(V1.594+V6.315+Fe0.103+)O20.02(H2O)2.9. The calculated density is 3.21 g/cm3. The mineral conforms to a series of synthetic vanadium bronzes, typified by Ag1-xV2O5 of known structure. It represents a new series of layer vanadate minerals of general formula MxV8O20·yH2O, similar in properties but distinct from the hewettite series (MxV6O16·yH2O).
Some aspects of Tertiary acid magmatism in NE Ireland
Authors: Meighan I. G. , Gibson D. , Hood D. N.
Published: December 2006

Geochemical data (including REE determinations) are presented for all five Mourne Mountains granites and three Northern Ireland rhyolites. These confirm (1) the extremely fractionated nature of some of the rocks (Sr and Ba < 10 ppm, Rb > 400 ppm, Eu/Eu* < 0.1, and K/Rb < 100), and (2) a major revision to the outcrops of the E. Mourne granites G1 and G2 in which much of the former is reclassified as G2. Combined petrographic and geochemical studies have also indicated that magmatic pulses were involved in the emplacement of Mourne intrusions G2 (Revised)-G5 inclusive.

The N. Ireland Tertiary acid rocks exhibit general geochemical similarities to their analogues elsewhere in the British Tertiary Igneous Province (in which Sr is generally < 100 ppm and CeN/YbN generally < 8 with Eu/Eu* often < 0.6), but as a suite the Mourne granites are enriched in Rb and some other LIL elements relative to their N. Arran counterparts.

The more fractionated acid magmas of NE Ireland are believed to have evolved from primitive granitic parent liquids by crystal fractionation at depth which involved major and accessory phases (including zircon and allanite). In the Mourne (and County Antrim) areas the primitive acid compositions lie at the ends of basaltic (tholeiitic) differentiation series, and in the Mourne central complex there is a complete geochemical sequence from basic rocks through intermediate members to primitive and ultimately highly evolved, subalkaline, granitic intrusions. It is concluded that the data are consistent with the Mourne granites and Northern Ireland rhyolites being essentially basaltic differentiates, although Sr isotope evidence indicates some (probably minor) crustal involvement.