A single crystal boule of cubic Gd₃Ga₅O₁₂ garnet doped with Nd, which was grown by the Czochralski technique, was optically examined by using microscopic and Sénarmont methods. The crystal contained deformed zones and consequently showed the striations interleaved with undeformed zones. The zonal striations show the convex shape parallel to one another and are nearly perpendicular to the [111] growth axis. The birefringence of the deformed zones was estimated as 10^-6 in the order of magnitude. The axis for large refractive index is nearly parallel to the growth axis, while the axisfor small one is nearly parallel to the striations, though the axes are slightlyinclined at point to point of the striations. The distribution of birefringence along the striations was analyzed to be larger from the core towards outer periphery of the crystal boule.

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Tetrahedrite has been found in scale from two wells in the Nigorikawa geothermal field, southern Hokkaido, Japan. The mineral occurs as irregular crystals up to 40μm in size with calcite, Stevensite and/or quartz, anhydrite, chalcopyrite atthe surface of calcite crystals formed on the well walls at depths between 980 and 1030 m of Well N-1, and at depths between 1680 and 1720m of Well N-2, particularly. The tetrahedrite from Well N-1 is chemically homogeneous, but a clear difference exists in the mineral assemblage and chemical composition between the two wells. Physical conditions of formation of tetrahedrite can be well explained on the basis of singlephase flow analysis in a wellbore ; the tetrahedrite precipitationoccurs mainly at the depth where the single-phase deep fluid begins to separate into initial two phase boiling fluid on its way upward the well head. The pressure and temperature of fluid at the depth of initial flash point where tetrahedrite precipitates at Well N-1 are 92 bars (44 bars Pco₂) and 260°C, andthe concentrations of Fe, As and Cu in the calculated deep fluid are 0.59, 5.8 and <0.01 mg/l, respectively.

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Until the middle of the seventeenth century, studies on crystal have been made in mineralogy. At the end of the eighteenth, the classical crystallography as one part of mineralogy has been taken up into the academic system. On and after the nineteenth century, the crystallography has formed the own originl system, andhas developed in an intimate mutual relation with physics and chemistry as basicsciences. In the middle of the nineteenth century, the cristallography has developed as amodern science, and was differentiated into structural crystallography or mathematical crystallography, physical crystallography or crystal physics, and chemical crystallography or crystal chemistry. In these mutual relations, the synthesis of the branches has assumed the character of crystal sciences, and was permited in physics, chemistry and material science as a basic science and also in metallurgy, material technology, pharmancy and agricalture as applied sciences. The crystal science has developed as an interdisciplinary science and has grown into an intimate relation with other sciences. In this paper, we sum up the aspect of the progress by describing the epoch-making events and historical consideration of modern crystallography, concerned with other sciences, during the early nineteenth century up to the first half of the twenteenth century. Besides, we try to show the results of research summing them up in a chronological table as an additional remark.

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