Mineral parageneses and high-low inversion temperature of quartz at the Denbekoba deposit of the Amakusa pottery stone have been investigated by X-ray powder diffraction, differential thermal analysis and polarizing microscopy. The main constituent minerals of the pottery ores are quartz and sericite. Kaolinite, dickite, tosudite, rectorite, calcite, siderite and residual feldspar are also contained in some ores. The deposit is considered to have been formed by hydrothermal alteration subsequent to the intrusion of rhyolitic magma. The central zone of the alteration is rich in sericite, kaolinite and rectorite. Tosudite is abundant in the intermediate zone between the central zone and the weakly altered zone. The central zone appears to have been subjected to conspicuous alteration at a late stage.
The high-low inversion peak in the DTA curve for the quartz is broad and the peak temperature is 4-23°C lower than that of standard quartz. Quartz samples in the central zone have higher inversion temperature as compared with those in the outer alteration zones. Moreover, the quartz samples in the central zone also show another low-temperature broad peak which may be due to the quartz having formed in the late stage of the alteration.

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A study was carried out to determine the relationship between the configurations of mica flakes and the tensile strength of flake aggregates at rupture. The configurations of typical ruby muscovite flakes, with size (square root of flake area) of 100-1300μm and thickness of 1-10μm were measured by a microscopic method
A hypothesis on tensile rupture strength of flake aggregates was deduced, using the well-known Griffith theory on brittle rupture. It was found statistically that tensile strength at rupture of flake aggregates was inversely proportional to the 1.34 power of flake size, or to 0.49 power of flake volume. The correlation coefficient was-0.90 or-0.92, respectively.
Approximate agreement was obtained between observed and inferred multipliers.

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¹²⁹Xe nuclear magnetic resonance (NMR) spectroscopy was used to investigate the microporous structures of SiO₂-TiO₂ sol pillared clays. The chemical shift of xenon adsorbed in the pillared clays was measured as a function of xenon pressure on the samples prepared by air-drying followed by calcination at temperatures of 200°-500°C. From the chemical shifts extrapolated to zero pressure, the pore diameters were determined to be 1.0-1.04 nm, which is much smaller than the expansion of the basal spacing of about 3 nm by the pillaring, and rather comparable to the dimensions estimated from a nitrogen adsorption study. As for the pillared samples prepared by a supercritical drying, the ¹²⁹Xe NMR measurement gave a chemical shift corresponding to the pores having an average diameter much larger than those of the air-dried samples.

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The clay mineral composition in five sediments holding the fossils of dinosaur from the Early Cretaceous Tetori Group was discussed under the results of X-ray diffraction, thermal analyses and infrared absorption spectroscopy. The outline of the results is as follows:
Illite and chlorite were dominant in all samples from the Itoshiro and Akaiwa Subgroups. These clay mineral phases were classified into the type III stage, the Late Anadiagenesis to the Epidiagenesis, according to Aoyagi (1987). The iron contents in the octahedral layers of both illite and chlorite were higher in the minerals from the Itoshiro Subgroup than the Akaiwa's, presupposing these minerals constracted from almost ideal structure.
A small amount of kaolin minerals was found in each sediments from the Akaiwa Subgroup, but not in the Itoshiro Subgroup. Considerable amounts of quartz, feldspars, calcite, and organic materials were determined in all sediments samples.

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In the shell molding process, catalytic decomposition of phenolic resin on resincoated sand in the presence of sepiolite was investigated. Phenolic resin-coated sand mixed with sepiolite liberated less amounts of smoke and irritating gases than that without sepiolite not only in the molding, but also in the casting. The results indicate that the sepiolite has promoted thermal decomposition of the irritating gases as catalyst. The bending strength of the mold decreased with the increasing sepiolite contents.

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