The Yasu Granite pluton, 10km×7km, is one of the Cretaceous granites around Lake Biwa, southwest Japan. It was emplaced within the Jurassic accretionary complex of the Tanba-Mino Belt, and is situated within the Cretaceous Biwa-ko Cauldron (60km×40km). The Yasu Granite can be lithologically divided into the following three main rock-types: the coarse-grained, medium-grained and fine-grained types. All of them are frequently porphyritic. They are essentially biotite granites, and sometimes hornblende is contained. The coarse-grained granite occurs partry in the southern part of the pluton, and represents a deep-seated lithology. The medium-grained granite mainly occupies the southern part, and should be the predominant constituent of this pluton. The fine-grained granite is distributed in the northern half and represents the roof-zone lithology. Granite porphyry occurs only as thin dykes at several places within the pluton. The lithological variations should have been formed during the crystallization and also at the cooling stages of the magma. The fine-grained granite was formed by quenching due to a rapid degassing, which led to the transfer of solidus to a higher-temperature side in consequence of the decrease of water-vapor pressure. The coarse-grained granite was reconstructed and/or reequilibrated under long durated high-temperature conditions, followed by both the pneumatolitic and hydrothermal activities. The medium-grained granite was formed under an intermediate condition between the above two. The geological situation of the Yasu Granite is not yet confirmed whether it belongs to the ring-complex associated with the formation of the Biwa-ko Cauldron or not, despite of its lithological and geochemical similarities to those granites forming the ring complex.

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Icosahedral architecture is extremely rare in natural materials and prohibited in minerals (bulk crystals) because it involves fivefold axes which are not compatible with translation symmetry. Here, we review an interesting icosahedral domain structure found recently in natural pyrite framboids, which are microscopic spheroidal aggregates of equant, equidimensional pyrite microcrystals and are ubiquitous in a variety of geological environments. The icosahedral structure in framboids consists of twenty tetrahedral subunits in which the internal microcrystals are regularly arranged in a cubic close packing and essentially involves fivefold and threefold microcrystal distributions on the sections. This is the only close packed icosahedral assembly of micrometric particles found in the natural world. Similar icosahedral structure based on the poly-tetrahedral construction can be observed in some synthetic nanoparticles (nanoclusters) such as multiple twinned particles of Au, Pd, etc. and chemical vapor deposited (CVD) diamonds. However, there are large differences between these icosahedral nanoparticles and framboids in terms of the attributes of the constituent particles. For example, the former exist at atomic dimensions, whereas the latter are composed of single crystals which are 10^4 times larger than atoms. Therefore, investigating such a micrometer scale icosahedral self-assembly might play an important role in understanding the physical state and behavior of small particles from nanometer to micrometer scales and, potentially, also to macro scale structure.

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Several species of water, such as structural water molecule, structural hydroxyl and water inclusions, are contained not only in hydrous minerals and but also in anhydrous ones, and they show variable absorption spectra in the infrared light range between 3000 and 3700cm-1 Micro Fourier-transform Infrared Spectroscopy (mFT-IR) using additional apparatuses such heating freezing stage is enable to characterize water species, content and allocations in many minerals. As the results, different water species are present in pegmatite alkali feldspar, and both structural and mobile water molecules are confirmed for laumontite. In addition, it is exemplified for feldspar, amphibole and garnet that water allocations and contents are variable together with textural and compositional changes within a grain.

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Microtextures of alkali feldspars from the Kan-nonji grano-diorite-tonalite pluton were examined mainly by TEM. The principal textures are bead-like patch perthites associated with lamellar perthites. The textures are unlike the extensive development of patch perthites in the granite plutons. TEM observations clarified the presence of cryptoperthitic Ab-rich lamellae which are scattered between microperthitic Ab-rich lamellae. In some region cryptoperthites are replaced with microperthites. Irregular microcline, which is developed around Ab-rich patches with micropores, replaces tweed orthoclase of lamellar perthites. Triclinicities of alkali feldspars are zero except only one data of 0.06 in the marginal part. These data are contrast to triclinicities of the higher degrees up to 0.88 found in the Tanakami granite (Nishimura et al, 1990). It is estimated from these data that the catastrophic coarsening of the cryptoperthites to the patch microperthite occurred with the formation of abundant micropores during the hydrothermal stage. At the last of hydrothermal stage, albitization occurred in the Ab-rich phases of the patch microperthites. These reactions are principally comparable to those in the other granite plutons such as the Tanakami pluton located adjacently to the Kan-nonji pluton. It is considered that the characteristics of the alkali feldspars might be controlled by primary compositions and the lower degree of hydrothermal reactions.

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Mineralogy of various carbon minerals, such as diamond, graphite, fullerene, carbon nanotubes and shungite was briefly summarized and related studies were reviewed. Some typical occurences of nano-daiamond, graphite and other carbon aggregates in Antarctic carbonaceous chondrite were described by means of high resolution electron microscope. Their characteristic features were clarified.. It was suggested that carbonaceous chondrites may be classified into some types based on crystallinity of graphite and other characteristics of carbon minerals.

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One of the newly developing application of zeolites, zeolite heat-pump system, has been described as an educational model which gives students scientific interests on micro-porous materials such as zeolites, clays etc. The energy storage mechanism and temperature conversion of energy sources, especially the ice making process, will be visualized by operating the instrument. Details of construction method and materials necessary are shown with the working mechanisms and the principle of the heat-pump. Students are able to understand states of energy stored as various manner of water molecules, that is, vapor, water, ice and zeolitic water, which presents in mineral zeolites.

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