This paper reviews recent progress in analysis of crystal size distributions (CSD) and spatial dispositions of minerals in metamorphic rocks. Mineral growth in metamorphic rocks consists of two stages: the recrytallization stage in which nucleation and growth makes in progress by net transfer reactions and the annealing stage in which Ostwald ripening is operative. Minerals from contact aureoles will preserve the original CSD produced by nucleation and growth because it may suffer little annealing effects. Two distinct CSD patterns, however, has been reported from contact aureoles. One is that by Kretz, which shows nearly log-normal distribution, indicating time-dependent nucleation rate under the assumption of constant growth rate. The other is that by Cashman and Ferry, which shows CSD pattern caused by constant rates of nucleation and growth. Normal or log-normal size distributions of minerals from regional metamorphic terrain has been also an enigma, because such CSD can be produced either by Ostwald ripening, or by diffusion-controlled nucleation and growth. This paper will give an overview for the resolution of these problems.

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Possible minerals as a water-reservoir in the depleted mantle are reviewed and discussed based upon the recent developements in crystal chemical studies on high pressure hydrous and nominally anhydrous magnesium silicates.

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Recent high resolution transmission electron microscopy (HRTEM) and analytical electron microscopy (AEM) permit us to observe structural imperfection and chemical composition of minerals even at atomic scale. The performance of high resolution electron microscope is now surpassing 0.2 nm point-to-point resolution. Since the early seventies, when HRTEM was established in mineralogical studies, the real structures of minerals, such as crystal defects, intergrowths of different structure types, twinning, and exsolution lamella, have been investigated to obtain information about geological events and to understand crystal structures and crystal chemistry by this method. In this article crystal structure and crystal chemistry of sheet silicates and related minerals are reviewed. Some recent results of the studies on fine texture and fine structure of serpentine and mica minerals using HRTEM and AEM are briefly shown. Examples of atomic resolution images of sericite and antigorite, calculated HRTEM and conventional TEM images of muscovite, technological developments of HRTEM and utilization of TEM in mineral sciences for two decades are presented. Practical analytical method and analytical conditions in microanalysis by AEM and application to sheet silicate mineralogy are also demonstrated.

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Total Reflection X-Ray Fluorescence analysis (TRXRF) apparatus for the nondestructive characterization of semiconductor has been developed and applied to Si wafers for ULSI fabrication. Monochromatic X-Ray and other improvements enables us to carry out trace analysis as low as 10¹⁰ atoms/cm², distribution analysis and near-surface depth analysis, which has clarified the behavior of trace metals on and nearby surface. The effects of Fe, Ni and Cu on crystal defect generation were clarified by analyzing the same wafer, and the nondestructive tracing during treatments proved its utility. Ultratrace surface analysis on Si wafers as low as 10⁸ atoms/cm² is established by the impurity condensation technique with a chemical droplet.

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