Single-crystals of a pure synthetic zircon and of zircons doped with each one of B, S, Al, Ca, Mn and U were grown by a flux method. Several zircons doped with P and REE (Dy, Tm, Eu and Sm) in addition to each one of the above elements were also grown. These zircons were irradiated with the thermal neutrons (neutron flux = 8×10¹³n/cm²sec). After the irradiation, a unique type of photo-luminescence was detected in all of the Ca-, Ca-P-, B- and S-doped zircons. In the latter two zircons, a deep coloration of red-purple occurred. The zircons except for the above four did not change in the luminescence spectra and in coloration, even though the intense γ-ray radiation or nuclear fission took place in these crystals. This unique type of the luminescence may be caused from the luminescence center which was created by the charged particles such as α-particles or proton generated by Ca(n, α)Ar, B(n, α)Li and S(n,p)P nuclear reactions of doped elements. Although this luminescence center disappears after several months, it might be stabilized in the presence of REE in the zircons. This luminescence was the same type as detected in natural zircons (Type II).

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A new heating stage has been constructed for high temperature transmission electron microscopy (HTTEM) to investigate the phase transformation of silicate minerals. A furnace of tungsten resistance coils protected by threefold thermal shields is attached to a double-tilting side-entry stage and specimens can be tilted up to 10 degrees in both X- and Y-axes. This stage is workable up to 1300°C. To record instantaneous changes of the fine textures during transformation, an image processing system with image intensifier is attached to the HTTEM. The present HTTEM system has been successfully applied to the phase transition between high- and low-clinoenstatite at 1100–1150°C.

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Infrared spectra of twenty-one manganoan alkali-calcic amphiboles from manganese ore deposits in Japan and India were examined. Hydroxyl stretching bands can be divided into two regions: H-bands (3750–3685 cm⁻¹) and L-bands (3685–3600 cm⁻¹). The H-bands’ upward frequency shift is due to the electric field arising from alkali ions in the A site, and the intensities of the H-bands are proportional to the number of alkali ions in the A site, so that the A site occupancy for each samples has been estimated by the areal ratio of these H- to L-bands. The higher frequency H-band near 3724 cm⁻¹ is ascribed to K ions in the A site, and the lower frequency band near 3700 cm⁻¹ to Na ions. Frequencies and features of the medium strong bands in the range of 800–740 cm⁻¹ are sensitive not only to the A site’s alkali ions, but also to the kinds and amounts of the M4 site cations.

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