bluuebunny/crossref_metadata_2025_split huggingface dataset:
A chromian hydrogrossular from Jordanów, Lower Silesia, Poland
Authors: Heflik W. , Żabiński W. 
Published: December 2006

SummaryA new variety of garnet, a chromian hydrogrossular, has been found in a loose block of diopside-albite rock in a quarry of serpentinite in Jordanów, Lower Silesia. Its chemical formula is given. Although the water content of this garnet barely exceeds 1 %, the X-ray, thermal, infra-red spectrophotometric, and optical examinations give evidence that this water, in the form of (OH)4 groupings, substitutes for the SiO4 tetrahedra. The chromian hydrogrossular from Jordanów belongs to the numerous calcium-rich silicates that were formed there during the process of alteration of serpentinites by lime-rich hydrothermal solutions.
Synthesis of aenigmatite
Authors: Thompson R. N. , Chisholm J. E. 
Published: December 2006

SummaryAenigmatite with the formula Na4[Fe102+Ti2]Si12O14 has been synthesized hydrothermally, at 700 °C and 1000 bars PH2O, from an oxide starting material. The oxygen fugacity was controlled by means of an iron-wüstite buffer. An indexed X-ray powder pattern of synthetic aenigmatite is given, together with comparative data on two natural samples. One of the aenigmatites, from Kola, U.S.S.R., is known to be triclinic (Kelsey and McKie, 1964). The powder patterns of this and the synthetic aenigmatite are so similar that it is concluded that the latter is also triclinic, at least at room temperature.
Mesonorms of granitic rock analyses
Authors: Parslow G. R. 
Published: December 2006

SummaryA modification to the CIPW norm, to account for the presence of biotite or muscovite or both in granite rocks, is described. The modification is most significant in norms that have been reduced to three components and plotted on experimental phase diagrams, such as the systems Q-Or-Ab and Or-Ab-An.
X-ray powder data for idoerase
Authors: Domańska E. , Nedoma J. , Żabiński W. 
Published: December 2006

SummaryAn X-ray powder pattern of idocrase (vesuvianite) from Canzoccoli, Italy, has been indexed by the method described by Nedoma (1968a, b). The improved X-ray data collected in the paper can be useful in identifying this mineral and in discussing the influence of diadochic substitutions on the lattice parameters of idocrase.
Crichtonite, a distinct species
Authors: Hey M. H. , Embrey P. G. , Fejer E. E. 
Published: December 2006

SummaryConfusion over the status of crichtonite is due to the fact that de Bournon included two different minerals in his species: thin hexagonal plates are indeed ilmenite, as has been generally assumed, but the much rarer steep rhombohedra with basal plane are a separate species, with a distinctive X-ray powder pattern (three strongest lines: 3·39 Å,s; 2·875,s; 2·131,S) and a composition (Fe2+,Fe3+,Ti)1·71O3 with Fe2+:Fe3+:Ti near 8:7:33. There is a rhombohedral pseudo-cell containing three oxygens, with α 23° 19′, a 7·117 Å but there is some evidence of twinning, and the true symmetry is probably orthorhombic or lower.
Water in sphere-type opal
Authors: Jones J. B. , Segnit E. R. 
Published: December 2006

SummarySurface areas of ‘amorphous’-type opals measured by nitrogen-absorption techniques were not consistent either with the surface area of the spheres of about 2000 Å diameter observable by electron microscopy or with the thermal dehydration data. This apparent inconsistency can be explained in terms of a smaller particulate structure of the order of 100–200 Å shown by higher resolution electron micrographs. This structure also accounts for a marked shrinkage shown in dilatometer curves of this type of opal.
Olivine nodules and related inclusions in trachyte from the Jos Plateau, Nigeria
Authors: Wright J. B. 
Published: December 2006

SummaryA trachyte plug near Jos contains a suite of inclusions, commonly rounded and of large size, including olivine nodules, pyroxenites, and a variety of basic to intermediate plutonic rocks, as well as albite megacrysts.The olivine nodules are typical of those found elsewhere in alkaline basic lavas and widely interpreted as upper mantle fragments. Most of the other inclusions contain evidence of crystallization at high pressures, even the syenites, which are interpreted as plutonic equivalents of the trachyte; for the feldspar in them is sanidine-microperthite.Discovery of this inclusion assemblage in a trachyte provides further support for the thesis that alkaline salic lavas can be generated at sub-crustal depths, by partial melting beneath domically uplifted continental shield areas (Bailey, 1964).The Nigerian Cenozoic volcanic province lies in an area of regional uplift, and is characterized by scattered small volcanic centres rather than by major eruptive foci. High pressure inclusions are being found at an increasing proportion of these centres, suggesting that the magmas rose directly and rapidly to the surface from the upper mantle levels at which they were all (including the trachyte) generated.
Olivine, pyroxene, feldspar, and spinel in ultramafic nodules from Auckland, New Zealand
Authors: Rodgers K. A. , Brothers R. N. 
Published: December 2006

SummaryChemical, optical, and X-ray data are presented for forsteritic olivine, bronzite-enstatite, diopsidic augite, anorthite, and spinel from ultramafic nodules at seven localities in Auckland province. Olivine has a composition range from Fo79–93for large primary crystals to Fo80–100for smaller interstitial grains. Orthopyroxenes (En83–96) carry exsolution lamellae of clinopyroxene parallel to (100); clinopyroxenes are mainly diopsidic augites with exsolved bronzite. The plagioclase (An97) has high-temperature characteristics and a lattice structure probably transitional between primitive and body-centred anorthite. Spinels include chromite, picotite, ceylonite, hercynite, and magnetite. Element distribution indicates that the ultramafic assemblages attained equilibrium at temperatures near 1250 °C and at moderate pressures, corresponding to the melting interval of anhydrous basaltic magmas within the uppermost mantle.
The mineralogy of Egyptian serpentinites and talc-earbonates
Authors: Basta E. Z. , Abdel Kader Z. 
Published: December 2006

SummaryOptical, d.t.a., X-ray, and chemical analysis investigations were carried out on serpenttinites from various Egyptian localities and on their associated talc-carbonates. The serpentinites were proved to consist of pure antigorite, lizardite, or clinochrysotile, or of mixtures of any pair of these serpentine minerals. Lizardite, which is reported for the first time in Egypt, is found to be of common occurrence. Talc, tremolite, carbonates, chlorite, olivine, biotite, chromite, magnetite, goethite, and stevensite are the main admixtures. The talc-carbonates consist mainly of talc and magnesite, or magnesite, dolomite, and talc together with minor amounts of antigorite, magnetite, goethite, and occasionally a little chlorite or calcite. Spectrographic analyses of some of the magnetically separated serpentines have been carried out and the origin of the Egyptian serpentinites and talc-carbonates is briefly discussed.
The preparation of fused samples in X-ray fluorescence analysis
Authors: Hooper P. R. , Atkins Lynne 
Published: December 2006

SummaryA rapid fusion technique is described in which the Li2B4O7 bead is polished, not crushed. The reliability of the technique is illustrated by a series of precision tests and analyses of standard rocks, using a 2:1 Li2B4O7 : rock-powder dilution. It is also pointed out that such a low-dilution fusion method may be used for Na2O and trace element analyses with only a small loss in sensitivity relative to the unfused-powder method. Any fusion method has the advantages of greatly reducing absorption effects and eliminating particle-size effects.
Dadsonite (minerals Q and QM), a new lead sulphantimonide
Authors: Jambor J. L. 
Published: December 2006

SummaryDadsonite was previously described without a name: (mineral Q) from Yellowknife, N.W.T.; (mineral QM) from Madoc, Ontario, and Pershing County, Nevada. Material from a fourth locality (Wolfsberg, Germany) yields good powder patterns, identical with those of QM, and single crystal data identical with those for Q.Microprobe analysis of the Nevada and Wolfsberg samples gave, respectively, Pb 49·3, 50·8; Sb 31·7, 31·8; S 20·7, 20·3; sum 101·7, 102·9 %, giving Pb11Sb12·0S29·8 and Pb11Sb11·7S28·4, ideally Pb11Sb12S29 or 11PbS·6Sb2S3. Dadsonite is acicular [010], monoclinic, space group P2, Pm, or P2/m, with a 19·05, b 4·11, c 17·33 Å, β 96° 20′, Z = 1, Sp. gr. 5·76. The strongest lines of the X-ray pattern are 3·78 (7), 3·62 (6), 3·38 (10), 2·84 (7), and 2·79 Å (6).
Sulphosahs of the plagionite group
Authors: Jambor J. L. 
Published: December 2006

SummaryThree of the members of the plagionite group, fülöppite Pb3S8S15, plagionite Pb5Sb8S17, and semseyite Pb9Sb8S21, show linear correlations of cell volume and density versus PbS:Sb2S3 mol ratios. This relationship can be used better to define the nature of the fourth member of the group, heteromorphite, Pb7Sb8S19. The cell dimensions derived for heteromorphite are a 13·60, b 11·93, c 21·22 Å, β 90° 50′.
Retrogression of eordierite to kyanite and andalusite at Fishtail Lake, Ontario, Canada
Authors: Lal R. K. 
Published: December 2006

SummaryCordierite commonly alters to chlorite-sericite, called pinite. Besides pinite alteration, cordierite from the Fishtail Lake shows textural evidence indicating retrogression to kyanite, andalusite, and coarse flakes of chlorite. This is consistent with the experimental data on the stability of cordierite and may be expected to be limited to potash-deficient rocks, such as the cordierite-garnetgedrite bearing gneisses of the area. In common potash-bearing pelitic rocks, retrogression of cordierite results in the formation of sericite and chlorite. In gneisses containing sillimanite and cordierite, the breakdown of cordierite in this way results in the association of the three aluminosilicates (kyanite, andalusite, and sillimanite) in the same rock. The association of kyanite-andalusite in equilibrium probably suggests that the retrogression of cordierite took place close to the univariant line of kyanite-andalusite.
Zeolites of the elinoptilolite–heulandite type in sediments of south-east England
Authors: Brown G. , Catt J. A. , Weir A. H. 
Published: December 2006

SummaryClinoptilolite-heulandite is reported from Jurassic, Cretaceous, and Palaeocene sediments in south-east England. It occurs mainly in 1–20 μm size fractions, and is associated with abundant montmorillonite and often also with glauconite and amorphous silica or low-temperature disordered cristobalite-tridymite. Its mode of occurrence and the associated minerals suggest an authigenic origin, but there is no evidence that the source material was volcanic.
The determination of the orthoclase content of homogenized alkali feldspars using the 2̄01 X-ray method
Authors: Jones J. B. , Nesbitt R. W. , Slade P. G. 
Published: December 2006

SummaryForty-three natural alkali feldspars have been homogenized and used to correlatewith wt % K2O. The regression of Or onis Or (wt %) = 465·5(Å)-1877·5, and is comparable to that obtained on an exchanged orthoclase (Wright, 1968). A deviation from the Orville (1963, 1967) determinative line for synthetic sanidine-albite is greatest at the high potassium end of the series. The discrepancy is not caused by failure to homogenize or incomplete disorder. The presence of cations other than potassium and sodium, or cation deficiency, or both cannot be discounted as a cause.
Phase relations in some tholeiitic lavas
illustrated by the system
R2O3–XO–YO–ZO2
Authors: Jamieson Brian G. 
Published: December 2006

Summary
In order to aid the graphical presentation
of analyses of igneous rocks, a pseudo-quaternary
system
R2O3XO-YO-ZO2
has recently been used (O'Hara, 1968, fig. 4). To
test its ability to present the analytical data of
tholeiitic basalts, the analyses of selected lavas
have been projected into the system and then
sub-projected into two planes. Lines, which
represent the loci of liquid compositions in
certain isobaric, pseudo-univariant equilibria,
have been drawn on the basis of the melting
relations of the basalts. After reading the
pseudo-ternary phase diagrams resulting from the
sub-projections, some genetic aspects of the lavas
of Kilauea and Mauna Loa are discussed from a
phase equilibrium standpoint.
Further data on an ‘eclogite’ from the
Sittampundi Complex, India
Authors: Chappell B. W. , White A. J. R. 
Published: December 2006

Summary
New analyses of a garnet-clinopyroxene
rock (‘eclogite’) and its constituent minerals
from the Sittampundi complex of India are
presented. The rock has a composition comparable
with an alkali-poor tholeiite and this
composition, as well as the garnet (Py 51·5 %; Alm
32·7 %) and pyroxene (Jd 7·4 %; Ts 10·8 %) are
very similar to those from South Harris.
The apparent distribution coefficient
(K′Fe/Mg) for the
garnet-clinopyroxene pair suggests a temperature
of equilibration near 850 °C. Projection of the
experimental data of Green and Ringwood (1967)
down to this temperature suggests a pressure of
about 7–8 kb. This is well below the pressure of
the granulite-eclogite transition.
Contributions to the synthesis of
spessartine analogues
Authors: Hříchová Renata 
Published: December 2006

Summary
Many syntheses have been carried out in
order to establish the possibility of replacing
manganese in spessartine,
Mn3Al2(SiO4)3,
by various elements (Be, Mg, Ca, Sr, Ba, Pb, Cu,
Ni, Co, Fe2+, Sc, Yt, Zn, Cd)
as well as aluminium by Sc, Yt, Zr, Ti, Cr,
Fe3+ by a solid state
reaction. The syntheses were done by sintering
pellets of the desired composition at about 1100
°C for 5–10 hours under normal pressure. It has
been found that an inert atmosphere creates more
favourable conditions for the syntheses of
spessartine analogues, compared to the results
obtained in the open-air reaction, where often
spinel was obtained. All the reaction products
were submitted to X-ray and chemical analysis and
to IR spectroscopical examination.
The crystal structure of wardite
Authors: Fanfani L. , Nunzi A. , Zanazzi P. F. 
Published: December 2006

Summary
Wardite,
NaAl3(OH)4(PO4)2.
2H2O, has
a = 7·03 Å,
c = 19·04 Å; space
group
P41212
or
P43212.
Its crystal structure was solved by a
three-dimensional Patterson function computed
using intensity data photographically collected by
the Weissenberg method, and refined by successive
Fourier maps and least-squares cycles to a
R index 0·062 for 316
independent observed reflections.
The wardite structure is formed by layers
of Al and Na coordination polyhedra sharing
vertices and edges. These sheets, parallel to the
a axes, are connected
to each other in the c
direction by PO4 tetrahedra
and H-bonds. This structural feature accounts for
the perfect {001} cleavage of wardite and explains
the change that occurs in lattice parameters when
Al is substituted by Fe in avelinoite. The
relationships with the minerals of the trigonal
families of crandallite, woodhouseite, and
jarosite are also discussed.
Lithiophorite from the Leeht mines,
Tomintoul, Banffshire
Authors: Wilson M. J. , Berrow M. L. , McHardy W. J. 
Published: December 2006

Summary
The constituent manganese minerals of an
ore body located at the Lecht mines near Tomintoul
include cryptomelane and lithiophorite. The
latter, now known to occur extensively in soils,
was characterized by X-ray, thermal, and electron
microscope techniques. Lithiophorite yields a
distinctive differential thermal curve and this
was studied in some detail. A platy morphology is
revealed under the electron microscope and from
selected-area electron diffraction patterns it was
concluded that the b
parameter of the mineral is 8·73 Å, three times
the value determined by Wadsley (1952). As
suggested by Wadsley, this could arise from the
distribution of lithium ions. Chemical analysis
shows that the Lecht lithiophorite is slightly
unusual in that it has a high iron and zinc
content but is relatively low in cobalt. The
associated cryptomelane contains a significant
amount of thallium.
Bideauxite, a new Arizona mineral
Authors: Williams Sidney A. 
Published: December 2006

SummaryBideauxite is a new mineral found in specimens from the Mammoth-St. Anthony mine, Pinal County, Arizona. The composition is Pb2AgCl3(F,OH)2 with Pb, Ag, Cl, F by duplicate wet analyses. Z = 16, G. calc. 6·256, meas. 6·274 (at 24·2 °C). Crystals are isometric hexoctahedral with a 14·132 Å. Space group Fd3m. Crystals show a, o, d, m {113}, μ {114}, n {112}, φ {116}, and {029} in decreasing order of importance. Colourless, transparent with white streak. Isotropic with nD 2·192. le, almost sectile, withc onchoidal fracture. H = 3. Turns pale lavender in strong light. Low M.P. B.P. Decomposes in acids and warm NH4OH. Bideauxite is an oxide zone mineral found with leadhillite, matlockite, and anglesite. May alter to cerussite.
Hodrushite—a new sulphosalt
Authors: Koděra M. , Kupčík V. , Makovický E. 
Published: December 2006

SummaryHodrushite, a new sulphosalt of copper and bismuth, was found in the Rosalia ore vein at Banská Hodrušá near Banská Štiavnica, Czechoslovakia. It has chemical composition Cu8·12Bi11·54Fe0·29S22 (as determined by electron-microprobe method) close to Cu8Bi12S22. Symmetry is monoclinic, space group A2/m, lattice constants a 27·21, b 3·93, c 17·58 Å, β 92° 9′, measured density 6·35, calculated density 6·45 g/cm3. Microhardness 200 kg/mm2, anisotropic, weak bireflectance, creamy with pinkish tint, maximum reflectivity about 6000 Å. Crystals needle-shaped and striated along [010], colour steel-grey, quickly tarnishing to bronze. Associated with quartz, hematite, and chalcopyrite. Closely related to cuprobismutite.
A metallographic and microprobe study of the metal phases in the Weekeroo Station meteorite
Authors: Axon H. J. , Smith P. L. 
Published: December 2006

SummaryThe kamacite contains a general precipitation of micrometre-sized particles of exsolved taenite. Larger particles are found decorating Neumann lines and at kamacite grain boundaries. The coexisting kamacite and taenite appear to have nickel contents of 6·4 % and about 53%, which are consistent with a temperature of about 330–60 °C on the binary iron-nickel equilibrium diagram.
Medanitos and Putinga, two South American meteorites
Authors: Symes R. F. , Hutchison R. 
Published: December 2006

SummaryPetrographic descriptions, bulk chemistry, and partial analyses of several mineral phases in each stone are presented. Medanitos, previously classed as a eucrite, is now shown to be a howardite: Putinga is an equilibrated olivine-hypersthene chondrite.
Nucleation and crystallization studies of some glasses in the CaO-MgO-Al2O3-SiO2 system
Authors: de Vekey R. C. , Majumdar A. J. 
Published: December 2006

SummaryGlass-ceramics based on the mineral cordierite have good mechanical and thermal properties. They can be easily prepared from glasses whose compositions lie in the primary phase field of cordierite on the 5 % CaO plane of the CaO-MgO-SiO2-Al2O3 system. For uniform crystallization in the bulk, addition of a suitable nucleating agent is essential. The addition of 10–12 wt % of TiO2 is considered to be suitable for both ternary and quaternary glasses. During controlled heat treatment of these glasses extensive phase separation occurs. The nucleation and crystallization processes that follow have been studied by differential thermal analysis, X-ray diffraction, and light and electron microscopy. Some of the physical and mechanical properties of these glass-ceramics have been measured.
Crystallization of anorthite from CaO–Al2O3–SiO2 glasses
Authors: Bhatty M. S. Y. , Gard J. A. , Glasser F. P. 
Published: December 2006

SummaryThe X-ray powder diffraction pattern of synthetic anorthite crystallized from a CaO-Al2O3-SiO2 glass having the anorthite (1:1:2) molar ratio is identical with that reported in the literature, and also with that of a natural Japanese anorthite specimen. Increasing the CaO or SiO2 content of the parent glasses used for crystallization studies has no measurable effect on that portion of the powder pattern attributable to anorthite. However, glasses containing an excess of Al2O3 ranging from 5 to 10 mol % gave, after crystallization at temperatures below c. 1150 °C distinctively different powder pattern. Several powder reflections that are normally strong, such as , etc., were found to be virtually absent. Moreover, the chemical excess of Al2O3 did not appear as a separate alumina-bearing phase. Upon reheating these anorthites to temperatures above 1200–50 °C or upon crystallizing a fresh portion of alumina-rich glass above 1200-50 °C, only the normal anorthite powder X-ray pattern was obtained; the pattern also contained some reflections due to corundum (α-Al2O3). Examination of the anomalous low-temperature anorthite by electron diffraction shows that the apparent absence of some powder lines is caused by both albite and Carlsbad twinning, which occur on an intimate scale not exceeding a few unit cell repeats. From the unique manner of its occurrence, the twinning is believed to be associated with the inclusion of an excess of Al3+ in the anorthite.
The selection of grain-growth control additives for the sintering of ceramics
Authors: Budworth D. W. 
Published: December 2006

SummaryThe close interrelation between sintering and grain growth is discussed critically, and the necessity for control, but not suppression, of grain growth is established. A distinction between discontinuous and exaggerated grain growth is drawn, and the superiority of grain boundary films as grain-growth control agents is demonstrated. Work on the establishment of tentative criteria for the selection of grain-growth control additives for alumina is reviewed and discussed, and the extension of these ideas to the selection of NaF as a successful aid for magnesia is described.
Sintering and crystal growth of magnesia in the presence of lime and forsterite
Authors: Spencer D. R. F. , Coleman D. S. 
Published: December 2006

SummaryThe densification of pure magnesia was examined along with mixtures containing 0·5 and 1·0 mol % of calcium oxide and forsterite. The sintering behaviour at temperatures between 1400 and 1800 °C was studied and measurements made of changes in shrinkage, porosity, bulk density, and grain size for sintering times of up to 8 h at sintering temperature. It was found that both the 0·5 and 1·0 mol % additions enhanced the sintering of pure magnesia in the temperature range 1500–1700 °C Increased grain growth was found for mixtures containing forsterite but little change occurred for mixtures containing lime. Examination of the grain growth data showed that the mixtures obeyed a relationship: Time at temperature × Constant = (grain size)n, where n = 2 for the grain growth of pure magnesia and mixtures containing lime, but n = 3 for mixtures of magnesia with additions of a silicate such as forsterite. A value of 78 kcal/mole was obtained for the grain growth of pure magnesia, which agrees with other researches.The extent of the solubility of lime in periclase for each lime-magnesia mixture at each temperature was also examined using electron probe analysis and related to the sintering behaviour observed for these mixtures.