Scan electron micrographs are shown of (1) kaolinite and dickite which crystallized from solution within cavities, (2) kaolinite weathered from clastic primary silicate material, (3) residual kaolinite from primary silicate rock, (4) kaolinite above and below a basal unconformity on granitic rock, and (5) hydrothermally altered kaolinite. The texture of kaolin reflects the environment in which the clay was formed.

Euhedral crystals of kaolin minerals characterize cavity fillings. The weathering environment produces large crystal flakes of kaolinite, expanded books, mats of elongates, high porosity, and low bulk density (less than 2.0). The hydrothermal environment produces smaller crystals, singles, sheaves and packets of crystals, low porosity and high bulk density (2.0 and above).

The interrelationships of genetic environment of kaolin minerals and accompanying texture are discussed in light of available geochemical information.

Scan electron micrographs (SEM) show the textures of ball clay, plastic refractory clay, flint clay, and of kaolins from Cornwall, U.K., and Brittany, France. The texture of ball clay is a swirl and ragged-flake pattern. Plastic refractory clay shows a transition in texture from ball clay to plastic, semi-plastic, to semi-flint, and flint-clay. Flint-clay texture exhibits a matrix of tiny, compactly interlocked clay grains in which may be interspersed small, tight books and sheaves of kaolinite. The plastic to flint clays are interpreted to be sequential components of the flint-clay facies. In one sense they represent elements in clay diagenesis.

Kaolins from the Cornwall district, U.K., and Brittany, France, show more similarity than dissimilarity in texture. Evidence from texture suggests that while hydrothermal action at Cornwall initiated alteration of the granite, the last significant process of kaolinization there was weathering.

An apparatus for consolidating fine grained materials under controlled conditions of total stress, pore fluid pressure and temperature is described and the variation in chemistry of pore fluid expelled during compaction from a montmorillonitic material at 40°C is reported. The decrease in concentration of dissolved salts in the pore fluid is related exponentially to the effective axial pressure.

The interaction of telone with acid and base saturated montmorillonite furnished adsorption isotherms which possessed combined features of H (high affinity) and C (linear rising) class isotherms; a fall in pH, an increase in electrical conductivity and formation of chloride ions. The observations were indicative of a process of chemisorption, both at the planar and lateral sites of montmorillonites, followed by penetration and swelling of the substrate micropores with telone. A reaction mechanism for the process of chemisorption has been proposed.

Determinations of the molecular orientation of ornithine and 6-aminohexanoic acid on the surface of vermiculite using polarized i.r. attenuated total reflectance have shown that the ornithine molecules lay almost flat on the clay surface, except for a C–N bond projecting towards, and hydrogen bonded to, the surface. Ornithine formed two adjacent layers in the interlayer space, whereas 6-aminohexanoic acid formed only one layer. The terminal C-N bond of 6-aminohexanoic acid was at 46° to the surface, the plane of the carbon chain having a tilt of 34°, and the molecular axis sloped at 36° to the surface. The amino acids, thus orientated, were positioned in the interlayer space using van der Waals contact distances and hydrogen bond lengths obtained from i.r. spectra. The i.r. results agreed with two dimensional electron density projections. In the ornithine complex, some of the methylene groups were so close to the clay surface that interaction may have caused the marked reduction observed in the intensity of the C–H stretching vibrations.

Fourier syntheses have been used to establish the arrangement of organic molecules in the interlamellar regions of a 16.10 Å phase of ornithine-vermiculite and a 16.92 Å phase of 6-aminohexanoic acid-vermiculite. The organic cations form two layers parallel to the silicate surfaces in ornithine-vermiculite and in 6-aminohexanoic acid-vermiculite the organic cations form ascending and descending “stairs” from the silicate sheets.

Ornithine-vermiculite forms a true single layer polytype but by contrast 6-aminohexanoic acid-vermiculite is two-layered and has a true c axis of 34.09 Å. Since a two layered vermiculite was used as a starting material to prepare the organic complexes, exchangeable organic cations affect the stacking sequence of the silicate sheets.

Tosudite was found in the Hokuno pottery stone mine, Gifu Prefecture, Japan. The pottery stone ore body, altered from the Cretaceous rhyolitic rock, is composed of tosudite, interstratified illite-montmorillonite, kaolinite and quartz. Prepared by normal sedimentation method, the specimen is composed of 75.6% tosudite, 24.0% kaolinite and 0.4% quartz. The chemical composition of the specimen is SiO2 45.09%, TiO2 tr., Al2O3 37.31%, Fe2O3 0.94%, MgO 0.41%, CaO 1.94%, Li2O 0.45%, Na2O 0.09%, K2O 0.44%, H2O(−) 1.50% and ignition loss 12.11%. After subtracting the compositions of the impurities, the structural formula of tosudite is given as; interlayer cations K0.23, Na0.07, Ca0.86 + nH2O; ‘gibbsite’ layer Li0.76, Mg0.35, ${\rm{Fe}}_{0.29}^{3 + }$, Al3.34 (OH)12.00; silicate layer Al8.00 [Si13.83 Al2.17] O40.00 (OH)8.00.

Syntheses of tosudite were made from a starting material which is an interstratified illite-montmorillonite obtained from the same ore body. At 450°C, 400atm., reacting for 5 days, a tosudite-like mineral was synthesized.