The rare nickel telluride mineral melonite is identified from Jaduguda uranium ore, Singhbhum Shear Zone, Bihar, India. Its physical, optical, chemical, and paragenetic characteristics are described. The composition as obtained by EPMA is NiTe1.66Bi0.06 or approximately Ni3(Te,Bi)5. The association of melonite with molybenite in this ore deposit is unusual, since melonite is generally associated with tellurides of gold and silver. This is the first reported occurrence of melonite from India.

Scorodite from Kiura mine, Bungo, Japan, has been known for many years. However, owing to its diversity in crystallographical and optical properties as well as chemical composition from those of other localities there appears to be some doubts as to the identity of the mineral. It has even been suggested to be possibly a new mineral having a composition akin to that of scorodite. Some time ago a number of fine crystals were placed at our disposal by the courtesy of Dr. Kô, in addition to the recent acquisition by our Institute of a few rarely found beautiful druses of the mineral. It will therefore be worth while to describe some of its main features in detail.

The first occurrence of mpororoite and anthoinite outside the African Continent has been found in an altered skarn from the Kara mine, Tasmania, forming a white powdery mixture of the two minerals pseudomorphing scheelite. The wet chemical analysis of the mixture shows WO3, Al2O3, and H2O to be the essential constituents, proving the non-essential nature of Fe2O3 in mpororoite; the original mpororoite contained high Fe2O3 substituting for Al2O3. The thermal treatment of the mixture at 100°C for 6 hours in air brings about the conversion of mpororoite into anthoinite, which re-hydrates into mpororoite, although the associated anthoinite does not. The source of Al is ascribed to the decomposition of aluminian andradite in the skarn.

New occurrences of derbylite, Fex2+Fe3+4–2xTi4+3+xSb3+O13(OH), and graeserite, Fex2+Fe3+4–2xTi4+3+xAs3+O13(OH), have been identified in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. Derbylite occurs as prismatic to acicular black crystals in carbonate veins. Iron and Ti are replaced by V (up to 0.29 atoms per formula unit, apfu) and minor Cr (up to 0.04 apfu). Mössbauer spectroscopy confirmed the occurrence of Fe2+ (up to 0.73 apfu), along with Fe3+. The Sb/(As+Sb) atomic ratio ranges between 0.73 and 0.82. Minor Ba and Pb (up to 0.04 apfu) substitute. Derbylite is monoclinic, space group P21/m, with unit-cell parameters a = 7.1690(3), b = 14.3515(7), c = 4.9867(2) Å, β = 104.820(3)° and V = 495.99(4) Å3. The crystal structure was refined to R1 = 0.0352 for 1955 reflections with Fo > 4σ(Fo). Graeserite occurs as prismatic to tabular black crystals, usually twinned, in carbonate veins or as porphyroblasts in schist. Graeserite in the first kind of assemblage is V rich (up to 0.66 apfu), and V poor in the second kind (0.03 apfu). Along with minor Cr (up to 0.06 apfu), this element replaces Fe and Ti. The occurrence of Fe2+ (up to 0.68 apfu) is confirmed by Mössbauer spectroscopy. Arsenic is dominant over Sb and detectable amounts of Ba and Pb have been measured (up to 0.27 apfu). Graeserite is monoclinic, space group C2/m, with unit-cell parameters for two samples: a = 5.0225(7), b = 14.3114(18), c = 7.1743(9) Å, β = 104.878(3)°, V = 498.39(11) Å3; and a = 5.0275(4), b = 14.2668(11), c = 7.1663(5) Å, β = 105.123(4)° and V = 496.21(7) Å3. The crystal structures were refined to R1 = 0.0399 and 0.0237 for 428 and 1081 reflections with Fo > 4σ(Fo), respectively. Derbylite and graeserite are homeotypic. They share the same tunnel structure, characterised by an octahedral framework and cuboctahedral cavities, hosting (As/Sb)O3 groups and (Ba/Pb) atoms.

A twin-law study of the plagioclase indicated metamorphic origin of the charnockites and volcanic origin of the basic members of the charnockite series. The original volcanic products have been influenced by the later metamorphism, resulting in the various basic members. The twinning in the plagioclase is considered to be primary. The perthite in the charnockite is of orthoclase variety and indicates a higher temperature of formation than the charnockites of other areas containing microcline. The orthopyroxene in the charnockite series is hypersthene and the clinopyroxene is sahlite. Hypersthene is inferred to have formed at the expense of sahlite, hornblende, biotite, and garnet.

About two years ago an aboriginal at Alice Springs in Central Australia reported that at a spot near the western extremity of the McDonnell Ranges the earth, if thrown upon a camp fire, did not extinguish the flames, but on the contrary increased the blaze. To those who heard the story this suggested the occurrence of oil, and it was decided to make some investigations. With the assistance of the native the spot was visited and located on the map. A sample of a white substance, which stimulated the burning of faggots, was forwarded to Adelaide University for examination and proved to be potassium nitrate. As a consequence Mr. C. T. Madigan, B.E., M.A., and myself paid a visit of inspection to the locality.

This mineral tar, which, from its elasticity, though somewhat weak, resembles elaterite, is found at the Craig Well, near Dingwall.

It is an intensely black, lustrous, sticky substance, of the consistency of tar, and from its being associated with albertite it may be looked upon as a variety of that asphalt.

This amphibole is an important constituent of an albite-epidote-actinolite-chlorite-calcite-schist from the summit of Coronet Peak in the Wakatipu district, western Otago. The mineral is somewhat concentrated into folia and porphyroblastie crystals up to 5·0 mm. in length, and is markedly flattened parallel to the orthopinakoid so that sections cut parallel to the schistosity exhibit numerous porphyroblasts, deeply coloured, poorly birefringent, and showing rather poor cleavage lines (fig. 1 A and B; fig. 2 A). In slices cut across the foliation numerous elongated end-sections are to be seen with development of small orthopinakoids (fig. 2 B).

The refractive indices (±0·002) are α 1·635, β 1·650, γ 1·655; γ—α 0·020. The angle γ:c = 18° and 2V 60°±1° Pleochroism follows the scheme α pale yellow, β dirty bluish-green, γ deep bluish-green, with absorption γ > β > α.

The study of minerals, using X-ray goniomcters in place of optical I instruments, has proceeded far in recent years. It is now a common practice among mineralogists and petrologists to confirm the nature of a given specimen by X-ray methods when there is some doubt about the identification by the older methods. The occurrence of pseudomorphs sometimes leads to misidentifications even in crystals of large size. If the material is cryptoerystalline it may be almost impossible to make an identification by optical methods. In such cases X-ray photographs may be of great assistance.

Quetzalcoatlite is a new mineral from the Bambollita mine in the Sierra La Huerta near Moctezuma, Sonora, Mexico. The colour is Capri blue (R.H.S. 120A) with a pale streak. H = 3; G meas. = 6·05±0·3 G calc. = 6·12. Crystals up to 0·4 mm long were not measurable but are acicular to prismatic, hexagonal, with fair cleavage on {100}; a 10·097 Å, c 4·944, space group C632. Z = I. Strongest lines are 8·752 (100), 2·748 (70), 2·520 (42B), 3·531 (40), 3·273 (31), 1·766 (28), 5·054 (21), 2·250 (20). Electron probe analysis gives: CuO 20·3%, 18·9, 20·9; ZnO 41·2, 38·2, 38·7; TeO2 29·4, 31·3, 30·6. Water by Penfield method on 2.265 mg gave 10·1%. Empirical cell contents are Cu4·01Zn7·73Te3·04O8·88(OH)17·89 or Cu4Zn8(TeO3)3OH18. Pleochroic with ε = colourless, ω = pale blue-green; uniaxial (-) with εD = 1·740, ωD = 1·802. Named for the Toltec god Quetzalcoatl.

Ultrahigh-pressure and -temperature (P-T) experimental techniques have progressed rapidly in recent years. By combining them with X-ray diffraction measurements at synchrotron radiation facilities, it is now possible to examine deep Earth mineralogy in situ at relevant high P-T conditions in a laser-heated diamond anvil cell (DAC). The lowermost part of the mantle, known as the D″ layer, has long been enigmatic because of a number of unexplained seismological features. Nevertheless, the discovery of a phase transition from MgSiO3 perovskite to ‘post-perovskite’ above 120 GPa and 2400 K indicates that post-perovskite is a principal constituent in the lowermost mantle, which is compatible with seismic observations. The ultrahigh P-T conditions of the Earth’s core have not been accessible by static experiments, but the structure and phase transition of Fe and Fe-alloys are now being examined up to 400 GPa and 6000 K by laser-heated DAC studies.

The potash feldspar in the charnockites is orthoclase and they are inferred to have been formed around 700 °C. A twin-law study of the plagioclase indicates an igneous origin of the charnockites and pyroxene granulites. The KD values of the coexisting pyroxenes in the granulites are appropriate to equilibrium at 670 °C. A substantial substitution of A1 for Si in the values of the coexisting pyroxenes in the granulites are appropriate to equilibrium at 670 °C. A substantial substitution of A1 for Si in the Z group in all mafic minerals studied also indicates relatively high temperatures of formation. Almandine is pyroperich, a result of high pressure. The charnockites and pyroxene granulites are inferred to be formed under conditions of high pressure and temperature.

In mid-1949 the London Natural History Society set up a committee to investigate and record temporary geological sections in the London area. Among the earliest to be dealt with was the excavation in flood-plain gravel for the foundations of the Concert Hall for the Festival of Britain (1951). Samples of 100-200 grams were taken from two sandlentieles for heavy mineral investigation, and material from one of these, passing 60 mesh and washed by laevigation, yielded, on separation by means of a bromoform-benzene mixture of density about 2"73, an assemblage with abundant garnet, tourmaline, zircon, and kyanite, very occasional staurolite, cassiterite, and fluorite, and moderately abundant collophane.

Anyone who contemplates on a map the great size of this island in geographic extension, and its extraordinarily irregular outline, would conclude that it must be composed of various formations, and that the connections and dispositions of these must be intricate in the extreme.

The latter conclusion will, however, upon a more careful observation, be found to apply only to the western portion of the island. However deeply trenched by the sea iu its lower grounds, however persistently thrusting its cliffs oceanward in its higher, the ridged and furrowed outlines of the eastern, disposed in almost rectilinear sequence, indicate but one formation,—various as the members of that formation may in mere lithological features appear.

The new mineral yarzhemskiite, K[B5O7(OH)2]⋅H2O, was found in a halite–sylvite evaporite rock at the Chelkar salt dome, Western Kazakhstan Region, Kazakhstan. It is also associated with carnallite, polyhalite, gypsum, strontioginorite, satimolite and quartz. Yarzhemskiite occurs as separate thick tabular, short prismatic or equant crystals up to 0.5 mm × 0.7 mm × 1 mm and grains having irregular outlines up to 1 mm × 1.5 mm × 2 mm. The mineral is transparent, colourless, with vitreous lustre. It is brittle, the Mohs’ hardness is ca 2½. Cleavage is perfect on {100}. Dmeas is 2.13(1) and Dcalc is 2.112 g cm–3. Yarzhemskiite is optically biaxial (+), α = 1.484(2), β = 1.508(2), γ = 1.546(2), 2Vmeas = 75(10)° and 2Vcalc = 80°. Chemical composition (wt.%, electron microprobe, H2O was calculated by stoichiometry) is: Na2O 0.01, K2O 17.84, CaO 0.07, B2O3 67.21, H2Ocalc 13.91, total 99.04. The empirical formula based on 10 O atoms per formula unit is K0.98B5.005O7(OH)2⋅H2O. Yarzhemskiite is monoclinic, P21/c, a = 9.47340(18), b = 7.52030(16), c = 11.4205(2) Å, β = 97.3002(17)°, V = 807.03(3) Å3 and Z = 4. The strongest reflections of the powder XRD pattern [d,Å(I,%)(hkl)] are: 9.39(86)(100), 4.696(41)(200), 3.296(18)($\bar{1}$13), 3.130(19)(022, 300), 2.935(42)(220), 2.898(100)($\bar{3}$02, $\bar{2}$21, 310), 2.832(56)(004) and 1.867(18)($\bar{2}$25). The crystal structure was solved based on single-crystal X-ray diffraction data, R1 = 3.36%. The structure contains infinite chains built by boron-centred polyhedra. The basic structural unit of the chain is a double ring B5O7(OH)2 consisting of one BO4 tetrahedron and four BO3 triangles. K+ cations centre ten-fold polyhedra which form, together with the borate chains [B5O7(OH)2]–∝, layers linked with each other only via H bonds. The mineral is named in honour of the Russian geologist, petrologist and mineralogist Yakov Yakovlevich Yarzhemskii (1901–?), a specialist in petrology of evaporite rocks and mineralogy and genesis of boron deposits related to evaporites.

Kozłowskiite, ideally Ca4(Fe2+Sn3)(Si2O7)2(Si2O6OH)2, is a new mineral isostructural with kristiansenite and silesiaite, found as a band in the core of a zoned silesiaite–kristiansenite crystal from the granitic pegmatite at Szklarska Poręba, Lower Silesia, Poland. In tiny pieces kozłowskiite is pale brownish, with a calculated density of 3.775 g⋅cm–3 and a mean refractive index ~1.727. The triclinic crystal structure was determined with space-group symmetry C1: a = 10.0183(2), b = 8.3861(1), c = 13.3395(2) Å, α = 89.956(1), β = 109.039(2), γ = 89.979(1)° and V = 1059.40(3) Å3, although, similarly to kristiansenite, it is metrically monoclinic (Laue group 2/m) with α and γ angles equal to 90° and a = 10.0170(3), b = 8.3860(2), c = 13.3421(4) Å, β = 109.050(3)° and V = 1059.40(5) Å3. The seven strongest reflections in the calculated powder X-ray diffraction pattern are [d in Å (I) hkl]: 5.190 (73.2) 111, 1$\bar{1}$1; 4.569 (30.0) $\bar{2}$02; 3.153 (64.7) 004; 3.094 (28.1) $\bar{3}$11, $\bar{3}\bar{1}$1; 3.089 (100) $\bar{2}\bar{2}$2, $\bar{2}$22; 2.595 (27.2) 2$\bar{2}$2, 222; and 2.141 (30.6) $\bar{3}$31, $\bar{3}\bar{3}$1. Electron microprobe analysis gave (in wt.%) SiO2 39.46, ZrO2 0.35, SnO2 31.13, Al2O3 0.35, Sc2O3 2.65, total Fe as Fe2O3 5.06 (= Fe2O3calc. 2.26; FeOcalc. 2.52), MnO 0.71, CaO 18.42 and H2Ocalc. 1.48, sum 99.33. The empirical formula on the basis of 26O + 2(OH) and 16 cations (Z = 2) is Ca4.00(Sn2.52Sc0.47Fe2+0.43Fe3+0.34Mn2+0.12Al0.08Zr0.03)Σ4.00(Si2.00O7)2(Si2.00O6OH)2. The crystal structure of kozłowskiite was refined to an R1 = 2.12% for 4887 reflections with Io>2σI. The Ca and Si sites are occupied solely by Ca and Si, respectively, and three of four M sites: M2, M3 and M4, are dominated by Sn. Four hydrogen atoms present in the kozłowskiite unit cell are shared among the O17–O27 and O47–O37 oxygen atoms where O17 and O47 are OH groups forming relatively strong hydrogen bonds.

A Ca-poor rhodonite (CaO 1.31 wt.%), found in a quartz vein cutting manganese ore bodies, north of the Xanthi plutonic complex (northeastern Greece) was studied. Microprobe analyses with optical and physical properties are given. The cell dimensions, obtained by least squares calculation from direct θ value measurements on a Philips PW1100 single-crystal diffractometer are a = 7.626, b = 11.844, c = 6.702 Å, α = 92.44°, β = 94.28°, γ = 105.70°, V = 579.89 Å3, Z = 10, and space group P.