For Fe-doped lithium niobate crystal (LN : Fe 0.1 wt%) grown by Czochralski technique, the effects of oxidation and reduction state were investigated on the photoinduced birefringence change by Ar-laser irradiation (488.0 nm). (1) A high accuracy apparatus for the measurement of the birefringence has been developed (Sénarmont method). (2) In LN (undoped) the birefringence change is negligibly small (<10^-6) regardless of the state of oxidation or reduction. (3) In LN : Fe the change is between 1.5 X 10^-3 and 10^-4. (4) It is possible to prepare a sample, 'oxidized LN : Fe', in which the change is still kept for long time even after stopping the irradiation.

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During the course of studies on telluride minerals, we have re-examined one of the unidentified minerals described by Ishibashi (1956) using X-ray diffraction and EPMA methods, and identified it as tellurantimony (Sb_1.9-2.1Te₃) which has not yet been described in Japan. The other minerals associated with tellurantimony were also established to be altaite and native tellurium by the same methods and by optical microscopy.

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A comparison has been made from the practical point of view between the two computer-search-match programs of Johnson/Vand (G. G. Johnson, and V. Vand. Ind. Eng. Chem. 59, 19. (1967)) and SANDMAN (W. N. Schreiner. C. Surdukowski & R. Jenkins. J. Appl. Cryst. 15, 513 (1982) ), both of which have been routinely used in our laboratory for several years to identify the phases from the JCPDS X-ray diffraction data. SANDMAN is superior in most cases where the systematic angular errors may exist in the measured diffraction patterns. Normally, it can identify three or more phases making up of an unknown sample. Several algorithms incorporated in the SANDMAN program are briefly described.

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