The minor elements present in some rocks and minerals of the Rakha mines area, Singhbhum district, Bihar, India, have been determined by X-ray fluorescence spectroscopy. Geological and geochemical studies in different parts of this shear zone already favour a hydrothermal origin. Some of the minor elements concentrated in the sulphide ores are found in lower concentration in the epidiorite and the chlorite-mica schist; these are, however, present in abundance in the soda-granites that are closely associated in space to the east and west of the Rakha mines area. A genetic link between sulphide ores and soda-granite may be predicted although the sulphides in the Rakha mines area are not directly associated with the soda-granite.

Fibres of hematite in kidney ore are elongated at right angles to the c-axis. The fibre axis, which may be normal to a face of either of the hexagonal prisms {101̄0} or {112̄0}, may show an abrupt change of orientation along the length of a fibre. There is little preferred orientation around the length of the fibres.

It is confirmed that in some calcite satin spar the fibres are elongated parallel to an edge of the cleavage rhombohedron; in other fibrous growths the elongation is either parallel to or Perpendicular to c.

Translation lamellae in olivine crystals are generally considered to be a result of mechanical deformation of pre-existing crystals but a recent hypothesis suggests that they may be formed during the latter stages of olivine crystallization in olivine-rich rocks due to the stresses imposed by mutual interference. Olivine crystals showing well-developed translation lamellae occur in the ultrabasic dykes of south-west Skye and it is demonstrated that these lamellae are unlikely to have been formed by mutual interference. Possible origins of the lamellae are considered and it is concluded that they are most likely to have been formed by tectonic deformation at elevated temperatures prior to the intrusion of the dykes.

From a metallographic examination it is suggested that Rancho de la Pila is a shock-hardened octahedrite; Murnpeowie is a cosmically reheated meteorite of unusual composition; Kopjes Vlei may have been produced by the reheating of a shock-hardened hexahedrite either cosmically or on earth; Braunau shows signs of preterrestrial reheating but Arltunga is a nickel-rich ataxite with no signs of metabolic alteration.

The minor elements Li, Sc, V, Cr, Co, Ni, Ga, Rb, and Sr have been determined in a number of diopsides and horneblendes from ultramafic rocks of the Gussevogorsk, Baranchinsk, and Nizhne-Tagilsk massifs in the Urals. Actinolite and anthophyllite are rare contact metamorphic products ; they too were analysed. The diopside and hornblende from the earlier-formed rocks, richer in olivine, contain more Cr and less V and Ti than those from the later-formed rocks.

Values of Δ2θ131-13̄1(Cu-Kα) have been determined for albites crystallized in the system NaAlSi3O8-β-LiAlSi2O6-H2O at various pressures, temperatures, and times. These values are consistently higher than those reported by MacKenzie (1957) for pure synthetic albites crystallized under similar conditions. Data of the present study have been combined with that of Stewart (1960) for albites crystallized in the system NaAlSi3O8-LiAlSiO4-H2O and, when plotted against bulk Li2O content, show constant Δ2θ131-13̄1 values at approximately 1·0 wt. % Li2O. The addition of Li to albites has a much more pronounced effect on the Δ2θ131-13̄1 parameter than the addition of K or Ca. Albites from lithium-rich pegmatites have much lower Δ2θ131-13̄1 values and are similar to those of synthetic low albites. The differences in this parameter between the natural and synthetic specimens are believed to be caused by differences in the structures of the coexisting lithium minerals in the natural and synthetic environments.

Calcium hexaluminate has recently been confirmed as a stable phase occurring within the system CaO-Al2O3. In the present investigation, this aluminate has been synthesized from the constituent oxides and its X-ray, optical, and physical (microhardness and reflectivity) properties determined. Similar data have also been obtained on the ferrian phase from the immediate hot-face zone of high-alumina bricks that had been in service in electric arc furnace roofs. An electron-probe microanalysis study revealed that between 12 and 13 % atomic replacement of Al by Fe had occurred in this ferrian calcium hexaluminate. The melting behaviour of the pure compound has been studied by firing pellets in a specially-constructed vacuum furnace. Results show the incongruent melting point to be 1870°C (±10° C), while the liquidus temperature is 1970° C (±10° C). These points were determined by examining polished sections of compacts heated within the range 1820 to 2000° C. A revised phase diagram of the high-alumina portion of the system CaO-Al2O2 is presented.

Synthetic mixtures of CaO and Fe2O3 fired in air at temperatures in the range 1180° C to 1240° C in some cases lost oxygen and formed ferrous-iron-bearing compounds. Samples after firing were examined by incident light microscopy and X-ray diffraction; new powder data are presented for the phases reported. In addition to α-Fe2O3, CaFe2O4, and Ca2Fe2O53. four distinct phases have been identified. These are and two forms of , described previously by Braun and Kwestroo (1960). The likely compositions of these phases are given.

Segregations of compact chlorite from ultramafic belts in New South Wales have been examined using chemical, X-ray, differential thermal, and electronprobe techniques. The chlorites vary from pennine to sheridanite. Some segregations occupy the central zone in metasomatic sequences of altered chromite, chlorite, and lizardite; but others may have formed at junctions of serpentinite and rodingite.

A number of new alkaline-earth-rare-earth silicate and germanate compounds with the apatite-type structure have been synthesized including a new calcium lanthanum silicate, Ca4La6(SiO4)6(OH)2, which has a 9·63 Å, c 7·12, and c/a 0·740. This has a random distribution of Ca2+ and La3+ over the (4f) and (6h) sites in the lattice. X-ray data are given for Ca4La6(SiO4)6(OH)2 together with cell dimensions for other synthetic silicate and germanate apatites. Silicate apatites with partially occupied or vacant halogen (2a) sites analogous to those of the pyro- morphites have been prepared, and a classification for silicate apatites based on synthetic end-members is proposed.

For chemical analyses with inaccurately reported H2O(+) or F, calculation of an amphibole formula on the basis of 23(O) after discarding the reported H2O(+) is in most cases as unsatisfactory as a standard calculation including H2O(+) based on 24(O, OH, F). The sum of the cations in X, Y, and Z groups most closely approaches theoretical values in a 23(O) calculation, but only by virtue of compensating and compounded errors of opposite sign. Realization of the ideal formula by either method without additional data is not an infallible criterion of accuracy of the analysis or the correct site occupation. These conclusions stem from the observation that although H2O(+) may be incorrect, most analyses add up to 100.00 or greater; thus compensating errors in metallic oxides are implicit.

Attempts to reproduce the X-ray measurements which led W. L. Brown to postulate the existence of monalbite at room temperature were unsuccessful.

A method for the preparation of chemically homogeneous powders by a weighing and gelling technique is described in detail. Stress is placed on the importance of the weight yield as an indication of the bulk chemical composition and on the chemical analysis of several portions to test the homogeneity. A list of recommended chemicals is included in an appendix.

From a metallographic study the thermo-mechanical history of Kodaikanal is proposed as a slow structure-forming cool, followed by mechanical damage, then mild reheating, and finally entry to earth.

Subsolidus phase relations in the systems ZnWO4-MnWO4, ZnWO4-ZnMoO4, MnMoO4-ZnMoO4, and MnWO4-MnMoO4, were investigated by using the quenching technique. A complete series of solid solutions forms in the system ZnWO4-MnWO4 above 840° C, whereas limited solid solubilities were found in the other three. The various limits of solubility are, at 620° C, 4·0 mole % ZnMoO4 in ZnWO4 and 4·0 mole % ZnWO4 in ZnMoO4, 13·0 mole % ZnMoO4 in MnMoO4 and 12·0 mole % MnMoO4 in ZnMoO4, 9·0 mole % MnMoO4 in MnWO4 and 6·0 mole % in MnWO4 in MnMoO4; and at 1000° C, 15·0 mole % ZnMoO4 in ZnWO4 and 15·0 mole % ZnWO4 in ZnMoO4, 36·0 mole % ZnMoO4 in MnMoO4 and 29·0 mole % MnMoO4 in ZnMoO4, 15·0 mole % MnMoO4 in MnWO4 and 27·0 mole % MnWO4 in MnMoO4.

Subsolidus phase relations in the system ZnWO4-ZnMoO4-MnWO4-MnMoO4 were studied at 900° C. The solubility of molybdenum in the (Zn,Mn)WO4 series increases from both end members to a maximum of 27·0 mole % at the composition Mn35Zn65. Both molybdates also have limited ranges of solid solutions, and a three-phase region occupies the central portion of the system defined by three points with compositions of 41 mole % ZnMoO4, 26 mole % MnMoO4, 33 mole % MnWO4; 57 mole % ZnMoO4, 10 mole % MnMoO4, 35 mole % MnWO4; and 27 mole % ZnMoO4, 34 mole % MnWO4, 39 mole % ZnWO4.