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.

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.

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.

Three metasedimentary enclaves up to a kilometre in length of contrasting compositions within the polymetamorphic Banded Gneissic Complex (> 2580Ma) have been studied for their mineral parageneses and metamorphic conditions. The largest enclave, consisting of kyanite-chloritoid-muscovite schist with quartz or corundum, and kyanite-fuchsite-corundum ± diaspore, was metamorphosed at most under lower amphibolite conditions, and is thus not isofacial with the surrounding schists and gneisses (of the ‘basement’ complex) which reached sillimanite-grade metamorphism in the last orogenic cycle (Aravalli: 1650–950Ma Orogeny) in Rajasthan.

The second enclave is a calc-silicate rock which occurs as a small lens. The presence of two generations of wollastonite which formed during different metamorphic events in the calcite-quartz-grossularite-anorthite-clinopyroxene assemblage indicates polymetamorphism.

The third enclave is a metabasic rock which records a complete polymetamorphic history in discontinuous zones in garnet coexisting with hornblende-chlorite-plagioclase-quartz±epidote. To explain the garnet zoning a model involving partial resorption of early garnet during the initial recrystallization stage of superimposed regional metamorphism is preferred to the alternative based on a single prograde metamorphism and retrogression.

The mineralogy of the calc-silicate and metabasic enclaves gives a recrystallization temperature of c. 700°C and a pressure in the range of 8–3 kbar during the second metamorphism.

A FORTRAN program has been written which inputs amphibole analyses, and outputs complete IMA-approved names, along with tabulated analyses, formula units, and IMA classification parameters. Several important corrections, additions, and amendments to the IMA scheme were found to be necessary. Two newly approved names have been incorporated—sadanagaite (ferro-pargasitic amphibole with Si < 5.5), and nyboite (alkali amphibole with (Na+K)A ⩾ 0.5, Fe3 ⩽ AlVI, Si < 7.5). The name anophorite (alkali amphibole with (Na+K)A ⩾ 0.5, Fe3 > AlVI, Si < 7.5) has been reinstated to complement nyboite, with the approval of the Amphibole Subcommittee of the IMA. Results of computer processing of several hundred analyses, which together cover the range of IMA-approved names, are summarized. These indicate substantial differences between IMA and previous nomenclature. The IMA-favoured procedure for reallocating total Fe in microprobe data is quite effective, except in kaersutites. Over half the analyses processed have anomalously high cations (e.g. Ca > 2), or cation totals (e.g. T + C + B > 15), commonly reflecting low H2O determinations. These prevent strict obeyance of the IMA site occupancy calculation rules. This problem can often be overcome by recalculation free of H2O, but other cases require modifications to the IMA rules. In particular, ‘misclassification’ of certain sodic-calcic amphiboles as edenite follows from transferring large excesses of C cations to the B site.

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.

The occurrence and genesis of Ca(OH)2 and Mg(OH)2 deposits associated with hyperalkaline groundwater from partly serpentinized ultramafic rocks in Northern Oman is reported. Two types of Ca(OH)2 deposit are differentiated; crystalline portlandite formed by the evaporation of Ca2+-2OH− spring waters, and a form of amorphous gel, not previously known in nature. The latter is a product of present-day low-temperature serpentinization. Mg(OH)2 (brucite) in both holocrystalline and gel forms is produced by mixing of Mg2+−2H surface waters with a Ca2+-2OH− groundwater in both surface and groundwater environments. These results indicate that significant differences exist between the processes of medium- and low-temperature brucite generation.

The chemistry of opaque spinel, delafossite (Cu2O·Fe2O3), cuprite (Cu2O), cassiterite, nickel-olivine (Ni2SiO4), and bunsenite (NiO) from some copper converter slags has been investigated by electron microprobe analysis. The spinel has a complex composition containing up to 33.89% NiO and 47.69% SnO2, ranging from essentially Ni2SnO4 to (Ni,Fe2+)O4. The associated delafossite contains up to 19.18% NiO and 38.15% SnO2. The chemical variation of the mineral phases is evaluated, and it appears that Ni2+ enters the spinel and delafossite to charge-balance the octahedrally coordinated Sn4+.

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.

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 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, 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.

Nelenite, (Mn,Fe)16si12O30(OH)14[O6 (OH)3], is a polymorph of schallerite and a member of the friedelite group. X-ray diffraction patterns can be indexed on a supercell with a = 13.418(5) and c = 85.48(8)A, space group Rm, but by analogy with TEM results on mcGillite and friedelite, the structure is based on a one-layer monoclinic cell with a = 23.240, b = 13.418, c = 7.382 Å, β = 105.21°, and space group C2/m. Chemical analysis yields SiO2 31.12, FeO 17.12, MgO 0.12, ZnO 3.63, MnO 29.22, As2O3 12.46, H2O 6.42, sum = 100.09%. Analysis of a number of samples indicates that Fe substitutes for Mn up to 5.8 of the 16 octahedrally coordinated cations, but that the Si: As ratio is constant. The strongest lines in the X-ray powder diffraction pattern (d, I/Io) are: 2.552,100; 2.878,70; 1.677,60; 3.55,60; 1.723,50.

Nelenite is brown in colour with a vitreous luster and perfect {0001} cleavage, which easily distinguishes it from schallerite. The Mohs' hardness is approximately 5. The density is 3.45 g/cm3 (calc.) and 3.46 g/cm3 (obs.). Nelenite is uniaxial negative with ɛ = 1.700 and ω = 1.718 (both ± 0.004). Nelenite was formerly known as ferroschallerite, which is a misnomer. It was found in the Franklin Mine, Franklin, Sussex County, New Jersey, in the 1920s. It occurs in several parageneses, associated with actinolite, tirodite, albite, garnet, feldspars, and several members of the stilpnomelane group in coarse-grained assemblages with pegmatitic texture and a breccia likely derived from this rock. Nelenite is named in honour of Joseph A. Nelen, chemist at the Smithsonian Institution.

Macphersonite is white, resinous to adamantine, hardness (Mohs) 2½−3, density 6.50–6.55 gm/cm3 and possesses a perfect cleavage on {010}. Optically it is negative with 2Vα 35–36°, α = 1.87, β = 2.00 and γ = 2.01, α = b, γ = c, and γ = a, dispersion r > v. Polysynthetic twinning, with either coarse or fine lamellae, is common, as are contact twins. Crystals are orthorhombic, tabular on b with a 10.37, b 23.10 and c 9.25 Å, cell volume 2215.8 Å3 and space group Pcab; Z is 8 formula units. The seven strongest lines in the X-ray powder pattern are 3.274 (50) 052; 3.234 (100) 251; 2.654 (90) 351,203; 2.598 (30) 172, 400; 2.310 (30) 004, 371, 0.10.0; 2.182 (30) 263; and 2.033 (30) 234, 452, 154, 1.10.2. Electronprobe-microanalysis-determined chemistry leads to the empirical formula (Pb4.08, Cu0.10, Cd0.07)Σ4.25S0.90 C2.18O10.55(OH)1.58 which yields the ideal formula Pb4(SO4)(CO3)2(OH)2 and hence macphersonite is a polymorph of leadhillite and susannite. The infrared spectrum shows basic similarities to leadhillite and susannite spectra with additional diagnostic absorption bands. Macphersonite shows an identical thermogravimetric behaviour to that of leadhillite. It is associated, in varying combinations, with leadhillite, susannite, cerussite, caledonite, pyromorphite, scotlandite, galena, and the ‘lead hydroxyapatite’ of Temple (1955). The new mineral mimics leadhillite.

Electron microprobe analysis of the new mineral scotlandite yielded Pb 72.27, S 9.95, corresponding to PbO 77.85, SO2 19.88, sum 97.73 wt.%. Secondary ion mass spectrometry showed the absence of Li, Be, B, C, N, and F, but the presence of very small amounts of Br. Infrared spectroscopy showed that the mineral is a sulphite with neither OH nor any other polyatomic anions. The empirical formula, calculated on the basis of Pb+S = 2 is Pb1.06S0.94O2.94 or ideally PbSO3.

The mineral has the following vibrations of the sulphite ion in the infrared spectrum: v3 920, 865; v1 970 (?); v2 620, 600; v4 488, 470 cm−1.

Scotlandite is monoclinic, with possible space groups P21 or P21/m. The unit cell dimensions are: a 4.542(2), b 5.333(2), c 6.413(2) Å, β 106.22(4)°, Z = 2. The strongest lines in the powder diffraction pattern are: 3.99(10) (011), 3.38(7) (110), 3.25(8) (11), 3.07(4) (002), 2.66(7) (020, 012), 2.56(4) (11), 2.24(5) (12, 102), 2.01(5)(210, 022), 1.707(4) (031), 1.538(4) (032, 004).

Scotlandite occurs as chisel-shaped or bladed crystals elongated along the c-axis, with a tendency to form radiating clusters. The following forms have been determined: {100}, {010}, {011}, {021}, {031}, and {032}. The new mineral has a pronounced cleavage along {100}, and a less good one along {010}. The crystals are pale yellow to greyish-white and colourless, sometimes transparent. Their lustre is adamantine, pearly on cleavage planes.

The mineral is optically biaxial positive, 2Vmeas. 35° 24' (Na). The refractive indices are: α ~ 2.035, β ~ 2.040, and γ ~ 2.085 (Na). Dispersion is strong, v >> r. The extinction is β//b, and α [001] = 20° (γ: [100] = 4°) in the obtuse angle β. H (Mohs) ≤ 2. D = 6.37 and calculated Dx = 6.40 g cm-3.

Scotlandite occurs in cavities in massive baryte and anglesite, and is closely associated with lanarkite and susannite; it represents the latest phase in the crystallization sequence of the associated lead secondary minerals. The label locality of the specimen is the Susanna vein, Leadhills, Scotland.

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).