This paper reviews current status on the crystal chemistry of the calcic amphiboles. Calcic amphiboles show a wide range in chemistry, and also have several crystallographically unique sites in the crystal structure. Consequently, our understanding on the crystal chemistry of the calcic amphiboles, especially hornblendes, has not progressed quite as rapidly as for the less complex silicate minerals. From 1960's to 1980's, the structure refinements of several calcic amphiboles were carried out, and cation distribution in the cation sites were discussed. As a result of the above investigations, cation distribution in hornblendes has beenrevealed. Namely, Al tends to occupy the T(1) site in preference to T(2) site inthe hornblende containing 0.5-2.0 pfu of^iv Al. In the metamorphic hornblendes, Al, Fe³⁺ and Ti occupy only the M(2) site, and Mg prefers the M(2) site to the M(1) and M(3) sites. On the other hand, the volcanic hornblendes indicate a more disordered cation distribution among the M(1), M(2) and M(3) sites than the metamorphic hornblendes.

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The abundance of hydrogen in olivines has been determined by secondaryion mass spectrometry (SIMS). Hydrogen implanted olivines were prepared for SIMSmeasurements as standards. A linear relationship was obtained between the relative hydrogen intensity ratio against the silicon and hydrogen concentrations overthe range of 100 to 25000 ppm H/Si.

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Recent X-ray diffraction analysis on electron-density distribution hasachieved a remarkable development, and structure refinement has been required tocorrect several factors such as extinction correction, thermal diffuse scattering, anharmonic thermal vibration. There were another problems on treatment of deformed distributions of 3d electron in transition-metal compounds. In this paper, three analytical factors to obtain accurate electron-density distributions, 3d electron-density distribution, anharmonic thermal vibration and extinction correction, were reviewed.

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There are two representative forming methods for ceramics such as pressure forming, which gives dynamic pressure to raw materials directly, and slip casting using capillalry attraction. In addition, there is an electrophoretic forming(electrophoretic and electroosmotic forming), which has been discussed as the third forming method, making use of surface charge of raw materials. Electrophoretic phenomena is explicated theoretically in an dilute system and there are many applications. However, it has a lot of unsolved problems in a concentrated system and its application is limited. And there are few industrial applications aiming at forming.In this paper, the fundamentals and the control factors of the electrophoretic (electroosmotic) forming, using natural inorganic materials as a starting material will be discussed. In addition, using these theory, continuous forming technology will also be discussed.

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