In-situ X-ray diffraction measurements were conducted for Mg₂GeO₄-olivine under high pressure at room temperature by using a diamond anvil cell(DAC) and a synchrotron radiation source in the National Institute for High Energy Physics as well as a conventional laboratory X-ray source, in order to clarify the possibility of a pressure-induced amorphization. The isothermal bulk modulus K₀=70(±5)GPa is obtained. The Mg₂GeO₄-olivine transforms to ‘X-ray amorphous state’ below 30GPa and the amorphous state is preserved during the decompression process to 0.1 MPa. The local structural instability caused by the change of the coordination of Ge atoms is likely to lead to the pressure-induced amorphization.

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Growth layers with mono-molecular and macroscopic step heights have been revealed for the first time on the (0001) surface of ilmenite crystals grown in a magma, occurring in the Aso-4 pyroclastic flow sediment. This successful observation was due to the leaching and dissolving the volcanic glass with diluted HF and HCl solution. The presence of such growth steps have also been ensured by the observations with the immersion liquid. All the observed growth steps are circular, but the ratios of step separation to step height are in the order of 10² in both thin and thick steps. The thinner step has a height of the unit cell dimension. This indicates that the magmatic ilmenite grew by the ordered Ti and Fe layer.

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Na-A type zeolite has been synthesized from the waste solution with the red mud exhausted from the Bayer process. The heats of water-vapor absorption of the Na–A and cation exchanged zeolites were measured by means of an adiabatic water-vapor absorption calorimeter which had been devised for investigating heat pump effect of zeolites. The integrated hydration enthalpy of A-zeolite is in the same order as those of mordenite and clinoptilolite. However, A-zeolite shows twice the total heat amount obtainable from unit weight samples of a natural zeolite, because natural zeolites contain impurity phases, and their dehydration amount around 100°C is much smaller. Mg-exchanged A-zeolite dehydrated at 100°C showed the largest amount of hydration enthalpy of 65.1kJ/mol, and a weight loss on dehydration of 14.7%. The Mg-A-zeolite will be the most efficient heat pump media of all zeolites dehydrated at 100°C in the present work.

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Chlorite and zoisite were observed as alteration products in a plagioclase from the archean anorthosite complex, Ontario, Canada. They were often grown as layers along cleavages of the host plagioclase. The orientation relations between alteration products and host plagioclase were determined using X-ray diffraction. C^*_chlorite was parallel to c^*_plagioclase. There are many chlorite grains where a- and b-axes of chlorite grains show no crystallographically significant orientation in (001) of plagioclase with keeping c^*_chlorite//c^*_plagioclase, A^*_zoisite was nearly parallel to c^*_plagioclase and b_zoisite was parallel to a_plagiociase. However, no lattice matchings were found between host plagioclase and the alteration products. It can be concluded that chlorite and zoisite grew on the surface of (001) cleavage of plagioclase according to the graphoepitaxy process.

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