Various internal textures of zircon from Cape Ashizuri Ring Complex, Kochi, SW Japan, were newly found by scanning electron microscope (SEM) and cathodoluminescence (CL) observations, and the chemical features including HfO₂, Y₂O₃, UO₂ and ThO₂ were described. Unusual internal textures of the zircon are classified into three types: Resorption Disturbance texture (RD), Local Disturbance texture (LD) and Hafnon-like Disturbance texture (HD). RD is cutting a part of original oscillatory zoning with rounded boundary, just like resorption-reprecipitation texture which commonly occurs in metamorphic zircon. LD is divided into two subtypes, LD1 and LD2: LD1 is developed at core and showing dendritic shape; on another front LD2 is mainly developed at rim and closely related to melt inclusions. Both subtypes have low concentrations of Y₂O₃ and ThO₂ and slightly high HfO₂ concentration, indicating that LD corresponds to recrystallized texture. HD is developing from zircon surface toward core deeply and associated with LD2. It has very unique chemical features: quite low Y₂O₃ and ThO₂ concentrations, twice HfO₂ concentration than that of igneous growth bands, and also nearly the same concentration of UO₂ as that of the igneous texture. The detailed phenomenon relating to HD formation is not clear. Through the observation, six growth stages of the zircon internal textures are suggested as follows: (1) igneous or hydrothermal core, (2) LD1, (3) RD, (4) igneous rim with enclosing melt, (5) LD2 around the melt inclusions and (6) outermost igneous rim. RD indicates ZrSiO₄-undersaturated environment, however all the other minerals from the Ring Complex except zircon have no record of such compositional change of the melt. In addition, RD and LD2 are observed in many zircons that have different compositions and included in different lithofacies. We think that these textural features may represent early magmatic events of Cape Ashizuri Ring Complex.

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  Magnetic minerals are distributed widely in the natural environment and are also present in a wide range of biological organisms, including humans. Magnetite-ulvöspinel and hematite-ilmenite solid solutions are the most common magnetic minerals in the Earth's crust. Their ability to record the past geomagnetic field depends on the crystal structure, chemical composition and geometric features of the consistent minerals. Magnetite and greigite crystals are also used as magnetic sensors in some microbes and animals, although their function is often still poorly understood. Recently, off-axis electron holography and Lorentz microscopy in the transmission electron microscope (TEM) have proven to be powerful techniques for studying geological and biological specimens, allowing both magnetic properties and crystallographic and chemical information to be imaged from the same region of a specimen. In this article, a selection of recent results that were obtained using these advanced TEM techniques is presented.

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  Life is ubiquitous not only in the near-surface environment where sunlight is converted into biological energy via photosynthesis, but also in the deep-sea and subsurface associated with chemical fluxes that sustain chemosynthesis. The present litho-hydro-bio-sphere has been shaped, at least in part, by intricate and diverse interplays between minerals and life forms in aqueous systems. Recent advances in technology that enables us to grasp nanometer-scale mineralogical features and to identify invisible microorganisms on the basis of their DNA sequences. As a consequence, the occurrence of, and mechanisms for, the biological formation and dissolution of many mineral phases have been unveiled. Several works that exemplify the progress in mineral-water-life interactions are presented in this short article.

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  The author has been dedicated efforts to accuracy improvement of gemstone identification by incorporating mineralogical aspects into traditional identification techniques. To cope with technological developments of synthetic gemstones and treatments, the author also applied various analytical laboratory techniques into gemstone identification. For instance, infrared spectral analysis is useful to classify diamonds into each type, distinguish natural stones from synthetics and detect impregnated materials such as resin in gemstones. CL method can be used to reveal growth history of a diamond crystal and this is applied to distinction between natural and synthetic diamonds. PL analysis is an effective technique to detect HPHT treatment in diamonds, while LA-ICP-MS analysis is effective to detect light elements such as Be that may be doped in corundum and it also can be applied to origin determination of gemstones such as corundum, emerald and tourmaline.

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