Lithium-bearing tosudite was found from a brittle clayey part of the Tooho “roseki” deposit, Aichi Prefecture, Japan. The chemical composition of the Li bearing tosudite was estimated as SiO2 41·60%, A12O3 36·40%, Fe2O3 1·82%, MgO 0·29%, CaO 0·38%, Li2O 1·04%, Na2O 0·14%, K2O 0·38%, H2O+ 11·12% and H2O− 6·87% from the chemical composition of a specimen with associated impurities. The Li-bearing tosudite has the regularly interstratified structure of montmorillonite and dioctahedral chlorite in which Li is present in a gibbsite sheet as shown in the structural formula of interlayer cations K0·16, Na0·09, Ca0.13 + 9·60 H2O; gibbsite sheet Li1·36, Mg0·14, Fe0·45, Al3·59 (OH)12·00; silicate layer Al8·00 (Si13·60, Al2·40) O40·00 (OH)8·00. The 29·48 Å reflection series of the Li-bearing tosudite moves to 31·3 Å after ethylene glycol treatment and to 23·3 Å on heating to 500°C for 1 hr.

Ethylenediamine (EDA) adsorbed from aqueous solution or vapor phase on Al-, Ca- and Mg-montmorillonite was retained to a more or less large extent in protonated form. The NH+3:NH2 ratio decreased with the polarizing power of the mineral exchange cation (Al > Mg > Ca) and with increasing amounts of amine fixed. Excess EDA was adsorbed through hydrogen-bonding with protonated species, and partially through co-ordination in vapor treated samples. Co-ordination to the exchangeable cation seemed to be favored in the order Al > Mg < Ca, and the complexes were stable up to 200°C. Heating lowered the NH+3:NH2 ratio, indicating some deprotonation process caused probably by the competition for protons between EDA and hydrolysed exchange cations. This competition might also account for the rather low quantities of NH+4 produced near 200°C.

The crystallinity of minerals in terms of crystallite size distribution and lattice perfection is quantified by means of statistical measures derived from X-ray line profiles (2 σ values). A low degree of crystallinity facilitates the non-stoichiometric incorporation of foreign elements in the crystal lattice. Crystallinity is affected by a number of factors and in natural profiles it may vary laterally as well as vertically.

For instance, goethite in laterite deposits shows decreasing crystallinity with increasing depth. Serpentine type minerals, on the other hand, show the lowest crystallinity at the surface where the degree of weathering is the most advanced. The presence of silica in migrating solutions prevents crystal growth and results in a low degree of crystallinity of minerals such as goethite. This has been observed in natural profiles and has been confirmed by laboratory experiments on the synthesis of goethite and sodium-birnessite. The crystallinity of minerals affects their response to extractive procedures. It could also be an important parameter in soil science.

An electron-microscopic and Mössbauer spectroscopic study of a range of kaolinites has revealed three distinct types of iron contamination within these minerals: a) Ferric ion may substitute for aluminium and be evenly distributed throughout the lattice, b) Ferric ion may be present as a crystalline coating of goethite, as indicated by lattice-imaging studies, or c) as an amorphous coating. The distribution of the iron in the groups b and c is non-uniform and is highest at the flake surfaces. Ferrous ion, when detected, is thought to be evenly distributed throughout the lattice. The size of the contaminating goethite crystallites and the observed Mössbauer spectra of these samples suggest that such particles are super-paramagnetic. All kaolinites can be cleaned by acid treatment except those having iron substituting for Al3+.

The exchange of [Co(NH3)6]3+ from its vermiculite complex has been carried out with a number of inorganic and alkyl quaternary ammonium ions of varying ionic sizes. The distribution and selectivity coefficients of the desorbing ions increase in the order: Li<Na<NH4<K<Rb<H<Cs for the monovalent, Ca<Mg for the bivalent and (C2H5)4N<(CH3)4N≪CTA (cetyl trimethyl ammonium) <CP (cetyl pyridinium) for the organic ions. The ΔG° values of some of the cation exchange reactions have been calculated by an equation of Kielland (1935).

Quartz isolated from soils by the pyrosulfate-H2SiF6 method and chert samples of various origins were examined with the scanning electron microscope. Quartz isolates of the 20–50μm from the A2 and B21t horizons of the Baxter soil (AR), with quartz δ18O of 18·2 and 19·0‰, respectively, showed a mixture of detrital quartz particles and chert clusters of aggregates of fine euhedral quartz crystals. The 2–5 μm fractions of both horizons consisted mainly of euhedral quartz particles. The 20–50 μm fraction from the underlying chert, with a δ18O = 29·6‰, consisted of aggregates of euhedral quartz particles 1–10 μm dia and of subhedral particles 0·1–0·5 μm dia. In the soil fractions, the size and shape of the quartz particles as well as oxygen isotope data indicated that the aggregates were from the underlying chert but that irregular, unaggregated grains were detritally admixed loess, particularly in the medium and coarse silt fractions. This mixing of chert (of low temperature origin and heavy oxygen) with detrital quartz (of high temperature origin and light oxygen) gave rise to the intermediate δ18O values in the soil quartz. The SEM of cherts of different geological ages showed different morphologies. Prismatic, polyhedral microcrystalline quartz of 1–10 μm size as well as submicron, euhedral particles were observed in cavities. Submicron, subhedral particles and interlocking quartz grains were characteristic of Precambrian chert. Quartz grains more than 100 μm in size isolated by HCl from Ordovician dolomite (WI) had large (many microns) subhedral overgrowths and attached clusters of 0·1–0·5 μm microcrystalline quartz. A Danish flint formed in chalk had calcite-lined cavities (x-ray emission determined) in which spheroidal fibrous chalcedony occurred.

The basic salts of this system were prepared and their structures and physico-chemical properties were studies by electron microscopy, chemical analysis, X-ray powder diffraction, thermal analysis, i.r. absorption spectra, BET absorption, and acidity-basicity measurements. The salts were found to be new compounds analogous to hydrotalcite. They can be expressed by the formula; where M2+ and M3+ denote di- and trivalent cations, A− and A2− denote mono- and divalent anions, respectively, and y = z1 + 2z2; z1 ≫ z2.

The structures consist of positively charged Cd(OH)2-like basic layers and intermediate layers formed from anions and water molecules with the solid solution of divalent cation (M2+) and trivalent cation (M3+) being formed in the range of 0.6 < x/(x + y) < 0.9. The anions of Cl−, NO3− and ClO4− are easily substituted by CO32−. A large part of the NO3− makes a monodentate-type bond and the ClO4− a bridge-type bond.

Glauconite-smectite and illite-smectite interlayered minerals are compared by various means in an attempt to establish the mineralogical relations between the two groups. Experiments at 2 Kb pressure and 200–350°C are reported as well as microprobe scans of pelletal glauconites. This new information is used along with published chemical data in order to establish that

(1) Illite and glauconite mixed layered phases appear to be crystallographically similar. Both series show the same relations between potassium (mica) content and the amount of smectite layers apparent in the interlayered structure.

(2) Illite and glauconite mica or mica-like phases can be separated on the basis of Fe and K contents.

(3) Probable phase relations of the two mixed layered mineral series indicate that, when the starting materials contain mixed layered mica-smectites, increasing temperature produces an iron-rich mica in the case of glauconite and an aluminous mica in the case of illite. The mixed layered phases present at intermediate temperatures are not the same for illites and glauconites.

Apparently there is no mineralogical or chemical continuity between illite and glauconite when the potassium content is 6 wt % or greater. It might be possible that the potassic interlayered minerals near montmorillonite or nontronite could form a continuous solid solution.

This review of the literature shows that there have been many attempts to modify or revise the original definition of halloysites as distinguished from kaolinites, which was based on the greater water content of the halloysites. In general, these various attempts have arrived at definitions of halloysites as distinguished from kaolinites that are based on one or more particular instrumental or chemical techniques. Further investigations with almost all of these techniques have shown the apparently clear distinctions of this kind to be misleading. All such instrumentally—or chemically—based definitions were shown to either complicate and confuse the distinction between halloysites and kaolinites or to provide only empirical and subtle distinctions. It is concluded that only the original definition, with slight adaptations, enables clear and unambiguous distinctions to be made between halloysites and kaolinites. It is noted, however, that a distinctive structure for halloysite has been postulated as a result of electron diffraction studies. Further studies of this kind could well establish such a structure as being definitive of the mineral species.

The literature also reveals a long-standing disagreement over the nomenclature of different forms of halloysite and particularly over the nomenclature of and distinction between the two forms of halloysite at the extreme ends of the hydration series. An analysis of experimental studies of the relationship between these two and other hydration states of halloysite reveals that forms of halloysite with all possible interlayer water contents between 0 and 2 molecules H2O per Al2Si2O5(OH)4 unit cell may exist and that the two end members of the hydration series may not be seen as distinct phases. The fully dehydrated halloysite is the only thermodynamically stable form of the mineral. A nomenclature system which was proposed by MacEwan in 1947 is consistent with these results. This system, amended only by the exclusion of the unnecessary term ‘metahalloysite’ should therefore be adopted in all studies of halloysites.

A 25°C, 1 atm total pressure phase diagram for the system SiO2-AlOOH-Fe2O3-H2O, is determined using the Phase Rule and Shreinemaker’s technique as in Chesworth (1974). The waterpresent assemblages so defined are equivalent to a kaolinitic stage of the goethite facies of the weathering zone. As such they constitute the ideal stable assemblages of several earth-surface deposits and the stage can therefore be used to construct models of these deposits.

The clay fraction of an Attic soil has been fired at temperatures up to 1100°C and the transformations induced by firing were studied by Mössbauer spectroscopy. The unfired clay contained iron in the form of small particles of α-Fe2O3 and β-FeOOH and as a substitutional ion in the clay mineral structure. A transformation of β-FeOOH to α-Fe2O3 is observed in the region of 200–400°C followed by dehydroxylation of the clay mineral between 500 and 800°C. A disintegration of the clay mineral structure is inferred above 800°C, followed by recrystallization in an iron-rich phase, most probably in the form of very fine particles. The room temperature spectra of the fired samples indicate that an increase in particle size of the oxides occurs upon firing.

Garnierite from the Tocantins Complex at Niquelandia, Brazil, is a 15Å, dioctahedral clay mineral, nickeliferous nontronite. The principal octahedral cations are Fe3+, Al and Ni. The ferric state of the iron has been verified by ESCA. Ni occupies both the octahedral site and an exchange site. The garnierite formed (and is still forming) by the weathering of nickeliferous pyroxenite. Although the garnierite is a secondary product of weathering, it undergoes further change as weathering progresses: Ni and silica decrease, Fe3+ and Al increase, and the color changes from bright yellow green to red brown. Eventual breakdown of the garnierite leaves mainly hydrated oxides of iron and aluminum.

Full and reduced charge smectite saturated with Na(I), Ca(II), Cu(II), or tetralkylammonium ions were swollen by a series of solvents of various bulk physical properties. In the full charge smectites, swelling occurred in all solvents regardless of the exchange ion or the initial water content. Charge differences did not usually result in differential swelling of the smectite. Little correlation was found between the degree of swelling and the Gutmann donor numbers, bulk dielectric constants, bulk surface tensions, or dipole moments of the solvents. The intensities of the high field Fe(III) resonance (g = 3.6) in the esr spectra of full charge smectite swollen in various solvents reflected variability in exchange ion positions and depended upon the Gutmann donor number of the solvent. Considerable variety in the stereochemistry of Cu(II)-solvent complexes was revealed by esr spectra of the swollen systems.