A new mineral, nukundamite, from a Fijian kuroko deposit is described. It has been referred to as idaite, Cu5FeS6, or Cu5.5xFexS6.5x. Electron-probe analyses gave Cu 56.51, Fe 9.64, and S 33.51, total with traces of Ag and As is 99.79%. Hexagonal with a 3.782, c 11.187 Å, Z = 1. Empirical formula Cu3.37, Fe0.66, S3.97 on the basis of eight atoms. Copper-coloured, metallic lustre, cleavage {0001} perfect. Density (g cm−3) 4.53 (calc), 4.30 (meas). Strongly pleochroic from reddish orange (Ro) to pale grey (Re). Parallel extinction. Very strong anisotropy with pale green-grey rotation colours. Reflectance values and quantitative colour values in air and oil are given. Similarities with the covelline structure are indicated.

An attempt to fully describe idaite from the Ida mine was unsuccessful. The description of the type material therefore remains inadequate.

The Precambrian Redskin stock is a high-silica alkalic granite that forms a late pluton related to the 1000 Ma-old Pikes Peak batholith. Zircon, fluorite, fluocerite, ilmenorutile, columbite, biotite, magnetite, and hematite are the most abundant accessory minerals. Thorite, monazite, and xenotime are sparse, and cassiterite and topaz very rare. The principal residences of Sn, Nb, and Ta are ilmenorutile and columbite. The occurrence of cassiterite intergrown with biotite and columbite and the high contents of Nb and Ta in cassiterite are evidence that cassiterite is also a primary mineral. The high concentrations of certain trace elements indicate a high degree of fractionation of magma prior to emplacement of the Redskin Granite. An extremely low crystallization temperature for the granite is indicated by the compositions of albite and K-feldspars, the presence of Fe-rich dioctahedral mica, the absence of Ti in magnetite, and the low content of Ti in biotite. This low crystallization temperature seems due largely to the high concentrations of F, Rb, and other volatile elements in the magma.

Ranunculite occurs as gold-yellow nodules. Mean diameter = 0.3 mm. Optically biaxial negative, 2V (calc.) = 56°. γ =1.670, β = 1.664, and α = 1.643. Monoclinic, pseudo-orthorhombic with a = 11.1 Å, b = 17.7 Å, c = 18.0 Å, and β ⋍ 90°. Z = 14. Measured density = 3.4 g/cm3. Calculated density = 3.39 g/cm3. The strongest lines of the X-ray powder pattern are (d, hkl, I): 9.00, 002–020 (100), 3.133, 330 (80), 470, 202–220 (50), 2.978, 006–060 (40), and 1.850, 600 (40). Chemical analysis by electron microprobe: Al2O3 9.9%, UO3 54.5%, P2O5 13.2%, H2O by thermogravimetry 20.3%. Formula: AlH(UO2)(PO4)(OH)3 · 4H2O. Ranunculite occurs at Kobokobo, Kivu, Zaïre, in pegmatitic rocks. The name after the colour (ranunculus = buttercup).

Pertinent general properties of the planets are listed. The condensation of the solar nebula is set in the context of stellar evolution and meteorites with sections on astronomical observations, chemical composition of the solar nebula, physical properties of the solar nebula, and chemical and physical aspects of condensation, accretion, and planetary differentiation. A cool nebula is preferred to allow survival of pre-solar grains with isotopic anomalies. Equilibrium progressive condensation of the solar nebula is regarded as a useful theoretical boundary, but complex processes involving crystal-liquid differentiation in, and collisions between, planetesimals are used to interpret the properties of meteorites and terrestrial planets. Chemical differentiation in the nebula begins with condensation and aggregation of dust, which can yield oxidized and reduced products depending whether C/O is less or greater than unity. Simple models for direct accretion of condensed materials into planets are reviewed but not adopted. Physical interactions involving small bodies include collisional accretion of dust-covered bodies, and differentiation of silicate and metal from mechanical, magnetic, and electrostatic forces. Physical and chemical differentiation involving large bodies involves head-on and glancing collision of planetesimals, orbital deflection, and disintegration within the Roche limit, and collision with debris rings and moons. Planetary accretion: dynamics, time scale, and heat sources involves more rapid growth of a larger body than a smaller one with ultimate development of one planet in each feeding zone, which flares out and ultimately overlaps with adjacent zones. Mars is small, and a planet did not develop in the asteroid belt, because of perturbations from Jupiter. The giant planets deflected material into the inner solar system. Melting of early planetesimals is invoked to explain differentiated meteorites. Chemical differentiation inside planet esimals and planets describes the phase equilibria for metal, sulphide, and peridotite, either dry, wet, or containing CO2. A wet body could begin crystal-liquid differentiation near 1250 K with sinking of Fe,S-rich liquid and rising of basaltic melt. The peridotitic residuum might undergo a subsequent differentiation at higher temperature under volatile-free conditions. Mineralogical storage of H2O, CO2, S, Cl, F, and alkalies is discussed. Chemical differentiation in planetary atmospheres briefly mentions escape of light species.

For the Earth, the early history is constrained by Archaean rocks dating from −3.8 × 109 yr whose properties indicate a non-reducing atmosphere, and a mantle that yielded volcanic rocks mostly similar to recent ones. The upper mantle (above 200 km depth) contains peridotitic rocks attributable to crystal-liquid differentiation and metamorphism. Volatile elements exist in mica and other minerals, but are sparse. Abundances of siderophile and chalcophile elements are high enough to require late accretion of material rich in these elements, the presence of a barrier between upper mantle and core, and some extraction by sinking sulphide. The mantle (deeper than 200 km) and core are inaccessible to direct study but interpretation of seismic data coupled with high-pressure laboratory studies requires inversion to dense phases in the mantle (especially perovskite?) and presence of light elements in the core (mainly S?). The bulk composition is modelled by cosmochemical analogy constrained by geophysical and geochemical parameters. The early condensate may be augmented by 1.5 ± 0.5? over (Mg+Si), and metal by 1.2±0.1?, while alkalies are probably depleted six-fold. Radial heterogeneity from a reduced interior to an oxidized exterior is suggested. For the Moon, sections cover observations, petrologic interpretations, and bulk chemical composition. For the origin of the Earth and Moon, age constraints, chemical constraints, and dynamical and accretional constraints allow comparison of suggested origins, with the conclusion that the Moon formed by either fission or disintegrative capture during early growth of the Earth, followed by simultaneous accretion coupled with disintegrative capture of planetesimals.

Mercury must be Fe-rich, but the silicate may not be just early condensate. For Venus, reviews are given of the surface properties, atmosphere, speculations on bulk composition and speculations on surface mineralogy and atmospheric compositions. The CO2 is in the atmosphere; most H may have been lost with concomitant oxidation of rocks; K/U ratios suggest basaltic and granitic rocks, and the high-surface temperature (c.740 K) implies granulitic metamorphism. For Mars, reviews are given of surface morphology, atmosphere and volatiles, mineralogy and petrology, and geophysical and geochemical models. Prolonged emission of Fe-rich lavas is suggested. Volatiles were removed by mineralogical processes from the atmosphere to give ice caps and sediments affected by aeolian processes and oxidation from photochemically generated H2O2. Fe-rich layer silicates, maghemite, and Mg-sul-phate may dominate the sediments.

The composition of comets and interplanetary dust may be inferrable from micrometeorites whose complex properties are suggestive of carbonaceous meteorites. Asteroids should be supplying at least many of the meteorites to Earth. A general description and review of remote-sensing studies culminate in a review of spatial descriptions and implications. The main belt is dominated by dark C-type asteroids assumed to be the primordial inhabitants produced by primary condensation and local accretion. The inner zone contains some brighter S-type asteroids interpreted as having undergone separation of metal from silicate as in stony-iron meteorites, as well as some E- and M-types perhaps matching enstatite-bearing meteorites and irons. Perhaps these differentiated(?) asteroids, as well as basaltic Vesta, are strays perturbed outwards from the inner solar system.

A review of meteorites covers carbonaceous meteorites, ordinary chondrites, enstatite chondrites and achondrites, reduced irons, forsterite-bearing meteorites and silicate inclusions in irons, irons, pallasites, chassignites and nakhlites, ureilites and lodranite, eucrites and shergottites, diogenites, howardites and mesosiderites, oxygen isotopes, and original location of meteorites. Emphasis is placed on mineralogical properties demonstrating crystal-liquid differentiation, brecciation, agglomeration, and even aqueous alteration and vapour transfer, though some evidence remains of direct condensation of gas to solid. The meteorites demonstrate the existence of many parent bodies (probably over 60), and most macrometeorites are ascribed to collision debris from the main-belt asteroids that has been deflected past Mars. The range of oxygen isotopes is explained by mixing of supernova debris rich in 16O with gas-solid differentiates of the nebula.

The culmination of the review is a suggested synthesis, which emphasizes a new model of heterogeneous accretion from planetesimals whose diverse compositions range from reduced material near Mercury to oxidized material from the asteroid zone outwards. Growth of a terrestrial planet begins from near-by slow planetesimals, and ends with distant fast planetesimals. Only the Earth and Venus are big enough to retain debris from late volatile-rich planetesimals deflected to high speed by the giant planets. Mercury, Moon, and Mars are volatilepoor. The Earth is zoned from a reduced interior, composed of crystal-liquid segregates of planetesimals captured early, to an oxidized exterior containing some material captured from outside the orbit of Mars. A mantle barrier hindered chemical equilibration. Hydrogen loss augmented oxidation. The mantle may be chemically zoned inwards from olivine-rich composition to pyroxene-rich composition, and the core should be reduced and contain substantial S and perhaps C and P. Mercury and Venus should have accreted reduced material, and only Venus should contain volatiles obtained from late planetesimals from outside the Martian orbit. Mars should have accreted mainly S-type asteroids, and have captured little volatile-rich material.

Uranium contents ranging from 0.03–1.18 ppm have been determined by delayed neutron activation analysis in a suite of 19 ultrabasic xenoliths (mostly of the common garnet lherzolite type) from the kimberlites of southern Africa. Consideration of these and previous data lead us to conclude that the U content of uncontaminated garnet lherzolite in the uppermost mantle is on average roughly 0.04–0.05 ppm, levels which are sufficient to account for the observed U contents of fresh basalts. Higher U contents in mantle-derived ultrabasic xenoliths are the result of secondary alteration processes, most probably related to infiltration metasomatism stemming from contact with kimberlitic or carbonatitic magma fractions. This introduced U is concentrated along the boundaries of the primary mineral grains and is mostly readily removed by acid leaching. A partial analysis is given for a secondary uraniferous calcium phosphate phase observed in kelyphitic rims around garnets.

Girdite, H2Pb3(TeO3)TeO6 is white, H = 2, D = 5.5. Crystals are complexly twinned and appear monoclinic domatic. The X-ray cell is a = 6.241Å, b = 5.686, c = 8.719, β = 91°41′; Z = 1.

Oboyerite is H6Pb6(TeO3)3(TeO6)2 · 2H2O. H = 1.5, D = 6.4. Crystals appear to be triclinic but are too small for X-ray work.

Fairbankite PbTeO3 is triclinic a = 7.81Å, b = 7.11, c = 6.96, α = 117°12′, β = 93°47′, γ = 93°24′, Z = 4. Indices are α = 2.29, β = 2.31, γ = 2.33.

Winstanleyite, TiTe3O8, is cubic Ia3, a = 10.963Å. Crystals are cubes, sometimes modified by the octahedron; colour Chinese yellow, H = 4, nD = 2.34.

All of the above species were found in small amounts on the waste dumps of the Grand Central mine, Tombstone, Arizona, associated with a wealth of other tellurites and tellurates.

The model for the amphibole and pyroxene structures based on close-packed oxygen layers introduced by Thompson is investigated systematically. It is shown that different features of it can best be understood in terms of three different symbolisms: the O and S rotations of tetrahedra; the A,B, C stacking notation for close-packed layers; and the c, h notation for the relationship of close-packed layers to their neighbours. The possible stacking arrangements and their space-groups are derived systematically. Relationships between the close-packed, fully rotated, model and the extended chain model are discussed, and some important drawbacks in the former model are pointed out, especially in connection with real amphibole structures.

Johnsomervilleite, Na10Ca6Mg18(Fe, Mn)25 (PO4)36 has Z = 3, a 15.00 Å, c 42.75 Å and cell volume 8330 Å3 and is a new rhombohedral species occurring in two metamorphic segregation pods in Moine gneiss of kyanite-sillimanite grade. Associated minerals are apatite, jahnsite, graftonite, mineral A, phosphosiderite, rockbridgeite, mitridatite, and vivianite. It is dark brown, brittle, and glassy, H = 4½, D = 3·35 (calc. 3.41) with a perfect basal (?) cleavage. Eight electron probe analyses are given and d spacings for 50 lines. The mineral, which is a Mg-Fe analogue of fillowite, is named after the late Mr J. M. Somerville who presented a specimen of garnet-quartz rock, which contained the new species, to the Royal Scottish Museum.

Rajite was found at Lone Pine, New Mexico, by R. A. Jenkins. It occurs as small (1.5 mm) crystals in rhyolite with mackayite, and may be a pseudomorph after teineite. Analysis gave CuO 18.4, 15.3, 18.0; TeO2 73.7, 79.8, 79.1; rem. (respectively) 7.9, 2.4, 2.3. Some CaO in samples 2 and 3: 2.5, 0.6%. This gives CuTe2O5, identical to the artificial compound prepared by Moret et al. (1969). Easily soluble in dilute acids; readily fusible.

Monoclinic P21/c with a = 6.866 Å, b = 9.314, c = 7.598, β = 109.1°. Strongest lines 3.064(10), 4.654(8), 3.348(8), 3.111(7), 2.744(7), 3.793(6B), 2.844(5), 2.796(5). With Z = 4, ρcalc = 5.77 g/cm3.

Crystals Duesbury green (RHS-131D), H = 4, ρmeas = 5.75 g/cm3. Pleochroic in greens γ > β > α; α = 2.115, β = 2.135, ‖ [010], γ = 2.26, α:[001] 22° in obtuse β, 2Vγ = 40°.

Glushinskite, a dihydrate of magnesium oxalate, occurs at the lichen/rock interface on serpentinite colonized by Lecanora atra at Mill of Johnston, near Insch in north-east Scotland. It is found in a creamy white layer intermingled with the hyphae of the lichen fungus. It consists of crystals mainly 2 to 5 µm in size showing a distorted pyramidal form, often with curved and striated faces. X-ray, infrared, and chemical data are given.

A new mineral species, vigezzite (Ca,Ce) (Nb,Ta,Ti)2O6, was found near Orcesco, Valle Vigezzo, Prov. Novara, Northern Italy. It forms fiat prismatic crystals up to 2–3 mm length of an orange-yellow colour. The crystals are elongated along the a-axis and flattened on (010). Cleavage at right angles to the prism axis is distinct, fracture conchoidal. Vickers hardness VHN = 396 kp/mm2, corresponding to in the Mohs scale. Refraction indices are high: α = 2.14, γ = 2.315 (NaD, 589 µm), birefringence is 0.175. Optic angle 2Vγ is large. Though intensively yellow coloured, the mineral shows no pleochroism. α = c, β = b, γ = a; optic axial plane is parallel to (010).

Vigezzite is orthorhombie with space group Pmnb or P21nb; a = 7.559±0.01, b = 11.028±0.01, c = 5.360± 0.004 Å, Z = 4. The six strongest lines of the X-ray powder pattern are 4.821 (9) (011), 3.784 (8) (200), 3.036 (10) (031), 2.974 (10) (211), 1.7129 (6) (242), 1.6018 (7) (431).

Electron microprobe analyses lead to the empirical formula (Ca0.82Ce0.24)Σ1.06(Nb0.9Ta0.62Ti0.5)Σ2.02O6. The mineral is not completely homogenous, the ratio Nb/(Nb+Ta) varies from 0.55–0.62. Rynersonite Ca (Ta,Nb)2O6, may represent the Ta-dominant equivalent of vigezzite. Vigezzite occurs together with several other Nb-minerals such as pyrochlore, columbite and fersmite, whose crystallographical and chemical data are reported, in an albitic rock of presumably pegmatitic origin.

The results of a study on the suitability of the inductively coupled plasma source spectrometer for the analysis of rocks and minerals are presented. The preparation of a stable solution of the elements to be measured is a prerequisite, and methods of sample preparation are described. It is shown that it is possible to measure all the major elements (excluding H2O and Fe2+) with acceptable precision and accuracy, and a wide range of trace elements down to the ppm level in the rock or mineral. Excluding sample preparation time, analysis and print-out of results as percent or ppm requires 1–2 minutes for complete analysis. Data on possible interferences (spectral line overlap etc.) are presented and, using some analyses of rocks and minerals comparisons are made with other analytical methods.

The Lower Cambrian Weymouth Formation at Nahant, Massachusetts, consisting of interbedded pelitic and calcareous rocks, was intruded by the Nahant Gabbro. The predominant metapelitic mineral assemblage of the contact aureole is quartz-muscovite-chlorite-magnetite-ilmenite. The calcareous hornfelses exhibit a varied mineral assemblage, and in some cases the variation can be spatially related to the intrusive. A number of cross-cutting thin mineral veins, many containing prehnite, are characteristically associated with these calcsilicate rocks.

The minerals have been analysed by electron microprobe and this work indicates the presence of a possible solvus in the Fe3+-Al epidote solid solution series. At the physicochemical conditions of the formation of the Nahant hornfelses, the ferric mole fractions of coexisting epidotes are 0.49 and 0.98.

Comparison with experimental work shows that the conditions of the contact metamorphism were T ≃ 500°C, Ptotal ≃ 2 kb, and XCO2 ≃ 0.2. However, the present assemblages are the result of a later low-grade regional metamorphism, the ultimate product of which was prehnite.

A spinel-phlogopite schist from the Mount Painter Province of South Australia forms part of a highly magnesium- and aluminium-rich unit and contains the minerals högbomite and taaffeite. Taaffeite nucleated in spinel during upper amphibolite facies metamorphism. During a subsequent upper amphibolite facies metamorphic event both spinel and taaffeite were partially replaced by högbomite. Chemical analyses of högbomite, taaffeite, and spinel are presented.

MacFallite, Ca2(Mn3+,Al)3(OH)3[SiO4] [Si2O7], is a new species occurring with manganite, braunite, orientite and pyrolusite blebs, stringers, and framboidal aggregates, which replace calcite in fissures and lenses in Keweenaw basalt near Manganese Lake, Copper Harbor, Keweenaw County, Michigan. It is rich reddish brown to maroon in coarse aggregates; compact massive material is brown to dull pink. The streak and powder are brown with a reddish tint. Lustre silky to subadamantine, specific gravity 3.43(2), hardness 5+, cleavage {001} perfect; twinning by reflection on {100} is universal. The mineral is monoclinic, space group P21, or P21/m, Z = 2, a 8.929(6), b 6.045(5), c 10.905(7) Å, β 119.10(3)°, α 1.773(5), β 1.795(5), γ 1.815(5), sign + or −, pleochroism α yellow, β light brown, γ dark brown, γ‖b. Orientite, Ca2Mn 2+ (OH)4[Si3O10]-Ca2 (OH)2[Si3O10] ·2H2O, orthorhombic, space group Cc2m, Ccm21or Ccmm, a 9.042(4), b 6.090(2), c 18.990(7) Å, α 1.765(5), β 1.79(1), γ 1.81(1), sign + or −, α brownish yellow, β reddish brown, γ deep brownish red, α‖a, γ‖b, also occurs in moderate abundance. It is turbid chocolate brown in platy masses but crystals are transparent rich reddish brown. Streak and powder brown. Observed forms are m{110}, c{001}, and poorly developed to absent α{100}, thin to thick tabular parallel to {001}, cleavage (or parting) {001} perfect, specific gravity 3.33.

A fumarolic origin is proposed for the assemblage, which in many respects is similar to the great manganese oxide deposits in Oriente Province, Cuba. Macfallite appears to be structurally related to pumpellyite while orientite is apparently related to ardennite.

A comparison of shield geotherms with the experimentally determined vapour-present solidus for kimberlite, indicates conditions of grazing incidence between 150–200 km, precisely where the mineral geotherms become disturbed. This relationship permits a new interpretation of kimberlite activity, by which volatiles migrating through cratonic lithosphere cause first metasomatism, and then incipient melting in the zone of incidence. Production of localized pockets of near-solidus liquid, erupted by accelerating crack propagation through the overlying lithosphere, is consistent with the unique set of features that characterize kimberlite. Volatile fluxing along steeper geotherms (away from craton nucleii) produces entirely different modes of magma eruption and development, by which highly under-saturated alkalic melts can reach the surface as liquids. Kimberlite activity is thus revealed as the limiting case of cratonic magmatism.

When diamond is synthesized at conditions of comparatively high temperature and pressure, the nucleation rate is high, as is the growth rate of the nuclei. Consequently the product is usually an aggregate of crystals with dendritic or skeletal structure. In this study the presence of gold or silver as an additive mixed with a catalyst was found to have the effect of suppressing nucleation. When a homogeneous mixture of graphite, catalyst, and additive was treated at conditions where skeletons and dendrites were produced in the absence of additive, euhedral crystals of octahedra were formed. When a special cell assemblage for high pressure experiments, in which the graphite was placed inside a cylinder of catalyst coated with additive, was used, prismatic and tabular crystals were synthesized.

Banded gneisses and migmatites in the Champira Dome contain assemblages of the biotite-cordierite-almandine subfacies of the granulite facies. The banded gneisses represent a sequence of arkosic sediments metamorphosed to sillimanite-cordierite gneisses. The migmatites were derived from more argillaceous and potassic sediments, with lower oxidation ratios and lower Ba/Rb ratios. They consist of a quartzo-feldspathic leucosome, representing anatectic melt, with schlieren of the refractory minerals sillimanite, garnet, biotite, and oxide minerals. Cordierite developed from garnet and biotite, except in rocks of high FeO/(FeO + MgO) ratio. Both rock types contain assemblages of magnetite + hercynite + corundum + ilmenite + hematite, formed by unmixing of high-temperature solid solutions. Rb-Sr studies of the banded gneisses gave an age of 2327 ± 25 Ma, which is interpreted as the date of metamorphism, and an initial 87Sr/86Sr ratio of 0.7064 ± 0.0003. The migmatite samples plot close to this 2327 Ma regression line, but the strontium isotopes were considerably disturbed, though not homogenized on the scale of sampling, 962 ± 34 Ma ago. It is considered that the anatexis in the migmatites was contemporaneous with the metamorphism of the banded gneisses and that the 962 ± 34 Ma event may be correlated with recrystallization of the migmatites accompanying the growth of cordierite.

Eleven specimens of natural or synthetic truscottite or gyrolite-truscottite intergrowth were studied by analytical electron microscopy and X-ray powder diffraction. The results suggest that, in absence of substitution, the formula of truscottite is Ca14 (Si24O58)(OH)8 · ∼ 2H2O. Truscottite can accommodate Al and K in absence of each other to the extents of 1.4 atoms of Al or 0.5 atoms of K in the above formula. Substitution of Al causes a small increase in cell dimensions, which can approach those of reyerite, but substitution of K has negligible effect.

Gismondine is a monoclinic mineral but prior to X-ray determination of its unit cell it was variously regarded as orthorhombic, monoclinic, or triclinic on account of its intricate twinning. A study of gismondine crystals from Osa Quarry, near Rome, indicates that the morphologically dominant form is {32} which by twinning about the normal to {100} produces penetration-twinned octahedral crystals united on (100) and (001). Gismondine has poor cleavage on {32} optic plane is (010) and γ:[001] = 42.5° (in obtuse β).