The material was collected from the manganese ore deposit of the Ichinomata mine, situated about 18km south of Yatsushiro City, Kumamoto Prefecture. Associated minerals are rhodochrosite, tephroite and hornstone-quartz.
Bementite forms semitransparent masses with various shades of brown. Under the microscope, practically monomineralic aggregate of very minute flakes of bementite. H=5½, d=3.03, α'=1.631, γ'=1.633, γ-α'=0.002.
Pyroxmangite is a minor constituent of the siliceous manganese ore of this mine. It occurs as porcelain-like masses with pinkish grey color. Under the microscope very fine granular. In places it appears as minute fibrous crystals, arranged radially and spherulitic. H=6, d=3.26, α=1.717, γ=1.732.
X-ray powder photographs, chemical composition and D.T.A. curves were examined on the two minerals and mineralogical problems concerning their relations to ganophyllite and rhodonite respectively were discussed to a certain extent.

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The authors have treated of pale-blue soft clay mineral produced from Niu Mine in Oita Prefecture as an item of their studies on nickelferous silicate minerals. Formerly this mineral used to de temporarily called “garnierite”, but it has been discovered through a couple of experiments that garnierite has properties different from the other and that it is equivalent to nickel-montmorillonite. That is to say, the nickel contained in that mineral is that which replaced a part of magnesium atom of montmorillonite and not that it was absorbed.
The other minerals coexisting with this mineral are kaolinite (not quite sure), dolomite, and opal. The two of the latter all contain a small quantity of nickel, but the greater part of the nickel is composcd of nickelferous montmorillonite according to analytical value.

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Mg-vermiculite occurs associated with anthophyllite or asbestos and talc in narrow belts at the margin of serpentine in contact with peagmatites at several places in Odaka and Uzumine, Fukushima Prefecture. Chemical analyses by H. Konno of specimens are as shown in table 1 and their chemical formula are calculated as Mg_0.37 (Mg_2.47 Ca_0.01 Mn_0.01 Fe_0.51) (Si_2.75 Al_1.22 Ti_0.02 Fe_0.01) O₁₀ (OH)₂·3.90 (H₂O) from Odaka and Mg_0.36 (Mg_2.60 Fe_0.40) (Si_2.85 Al_1.08 Ti_0.03 Fe_0.04) O₁₀ (OH)₂·4.59 (H₂O) from Uzumine.

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Supergene maghemite associated with hematite and goethite, occurs in the weathered surface of the contact-metasomatic magnetite deposits of Takanokura Mine, Fukushima Prefecture, Japan.
The mineral is identified by chemical analysis, X-ray powder analysis and differential thermal analysis. Oxidation process of the Takanokura iron oxide minerals are assumed as follows: Fe₃O₄→γ-Fe₂O₃→α-Fe₂O₃·H₂O
↓α-Fe₂O₃↑

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For the study of rectifying action of metalllic selenium, the author studied on the relations between minor impurities contained in selenium and crystal texture affected by temperature conditions.
Minor impurities added in selenium increase the electro-conductivity of selenium, and embody various nature as the semiconductors. And temperature conditions urge the occurrence of kernel and growth of hexagonal crystal and production of blocking layer. These are great factors that control the rectifying action, and have changed the forward current and reverse voltage remarkably.
Rectifying phenomena may be occurred by actions of positive hole for the potential wall, and these are derived from high resistance of the blocking layer producted on the selenium surface. Moreover, they may be considered to rectifying action for point contact with crystal growth surface and cathode metals.

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By digesting glassy tuff with alkaline solutions on the waterbath, the writer obtained sodalite and a zeolitic material. Studying in detail the products obtained by the reactions of glassy tuff with NaCl and NaOH solutions in various concentrations, the writers confirmed the conditions being favourable for crystallization of these materials. The longer the tuff was warmed in more concentrated solutions, the more sodalite was produced. Crystallization of the zeolitic material is favourable in a case of lower concentrations of these solutions. NaOH solution seems to behave as a catalyst for the crystallization courses.

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The fact that the enrichment of rubidium and cesium in carnallite has been pointed out by many workers.
The behaviour of trace amount of rubidium and cesium was studied during the crystallisation of halite, sylvite, bischoffite and carnallite, by isothermal evaporation of each of the saturatued solution by use of¹³⁷Cs and⁸⁶Rb as tracer.
Logarithmic distribution coefficients of rubidium and cesium between the crystal and the solution have been determined as follows : Logarithmic distribution coefficient of rubidium in halite was 0.14, in sylvite was 0.4, in bischoffite was 0.3, and in carnallite was 2.4, and that of cesium in halite was 0.02, in sylvite was 0.03, in bischoffite was 0.3 and in carnallite was 1.3.
Those results suggest that rubidium and cesium will be selectively concentrated in carnallite among the oceanic salts.
The actual samples of carnallite originated from the oceanic salt deposit in Stassfurt were analysed for chemical composition and X-ray diffraction pattern.
The results indicated that one of the samples was the mixture of carnallite, halite and kainite, and the other was perfect carnallite ; cesium contained 1 ppm. in the former and 2 ppm. in the latter, but the Rb/Cs ratio of the former was 90 and that of the latter was 85.
The similarity of the ratios and results of the above described experiment suggest that the rubidium and the cesium in the former impure carnallite sample are concentrated only in the carnallite.

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Chemical X-ray and thermal analyses with microscopic observation data are given for the some specimens of limonite ore from the Shinmei mine, Hokkaido, Japan.
The X-ray data are given the reflections line “goethite”. The Nakanosawa ore deposits of this mine is the impregnate or metasomatic type formed in Neogene Tertiary sediment. The ore bodiess take the lens or layer shape. Crystallinity of these goethite are different a part in the ore bodies.

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Enstatite occurs filling a fissure of pyroxenite and chromite body at the Ogiri level of Hirose Mine, Tari district, Tottori Prefecture. The mineral is formed in crystals associated with andradite containing chromium at comparatively high temperatures. It seems to the writer that the mineral represents a part of liquid magma left after the greater part of magma had crystallized.
The crystals are (010) tablets and the form is composed of (100), (010) and (101). The specific gravity is 3.234 and the hardness is 5½. The crystals are pale green and sub-transparent. In thin section, the mineral is colorless and the optical plane is (100). The refractive indices are α=1.664. β=1.667, and γ=1.672. The optical angle is (+) 2V=61.5° The chemical composition is given as follows : SiO₂ 54.01, TiO₂ 0.03, Al₂O₃ 3.95, Fe₂O₃ 2.07, Cr₂O₃ 0.57, FeO 1.57, MnO 0.00, CaO 0.99, MgO 35.65, NiO 0.09, K₂O 0.00, Na₂O 0.08, H₂O±0.59=99.60 (Wt%). The chromian enstatite of this kind has not been reported in Japan.

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On the basal plane of one crystal of hematite from an andesitic lava at Ayumikotan, Japan, three types of growth pyramids are described.
First type, which is called the “tetrahedral” growth pyramid, consists of many closely spaced, thin, concentric, equi-lateral triangular growth layers. (Photo. 2, 5) On some of these growth pyramids spiral growth and interlacing can be observed. (Photo 5 a, b) On some growth pyramids the layers on one side of the triangular are produced into a peak suggesting the presence of an imperfect screw dislocation. (Photo. 5a) Measurement by multiple beam interferometry (Photo. 4) and fringes of equal chromatic order (Photo.3) show that thinnest growth layrs are 2.3Å thick (I/6 of the unit cell). Further details may be seen in Table 1.
Second type is called the “triangular” growth layer. They are equi-lateral triangular growth layers on which no spirals have been observed. (Photo.7) It is suggested that growth took place by two-dimensional neucleation. The origin of the structure within the triangles and the linear arrangement of growth centres is described in the paper. (Photo.8, 9) At some distance from the growth triangles, a serrated structure, like sow-teeth, is developed. (Photo.6) This may also be seen around all growth pyramids of the first type. Measurements of thickness are shown in Table 3.
In the third type of growth pyramids (Photo.10, 11) the thickness of the layersin different cases varies from 1 to 4 unit cell including thickness of 2n+1/2 unit cell (see Table4). These growth pyramids seem to be formed by screw dislocation, as there is a pit at the centre of each growth pyramid. The type of interlacing shown by these growth pyramids (Photo.11) suggests that polytypism may be present.
From these observations it is deduced that this crystal has grown under the condition of comparatively high supersaturation.

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The growth and the epitaxy of various stalactites which occur in the Ezobanryu gorotto are discussed. So called “tube stalactite” forms as a monocrystalline or nearly monocrystalline slender tube, elongated along the C-axis. All tube stalactites are equally 4.5mm in diameter.
As to the lateral growth of this tube, three kinds of mode are observed.
1) When the velocity of the lateral growth is extremely slow, the tube grows into an adult “monocrystalline stalactite”, keeping its initial crystallographic orientation.
2) When the velocity is rapid, new nuclei develop on the wall of the tube and begin to grow radially. Orientations of the C-axis of new crystals are perpendicular to the axis of the tube.
The horizontal section of such a stalactite is much resemble to the sunflower and is named “sunflower stalactite”.
3) Observable is an intermediate case in which the velocity allows of the growth of the tube itself together with the development of new nuclei on it.
In such a case the tube continues to grow until it is enveloped, as a star-like form, in newly developing crystals. Such a stalactite is named “star stalactite”.

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The manganese mineralization occurred in three ages in Hokkaido. The older one is of Palaeozoic or Mesozoic ages, and the younger two of Miocene and Quaternary. Late Tertiary, especially the Miocene age is characterized by the most intensive and extensive volcanic activities. The mostly ore deposits are found this age and the only south-western Hokkaido.
The writer investigated the various modification of manganese dioxide and hydroxide minerals mainly from the mineralogical stand point and clarified of geological occurrence in late Tertiary. Some geologists suppose that the deposits are syngenetic ore beds precipitated from marine water, the manganese of which were supplied from manganese-bearing hot springs. But others postulate the hydrothermal replacement origin.
Manganese dioxide or hydroxide is one of the most familiar and common minerals found in various manganese deposits, but is mineralogical study is very equivocal owing to the variability and overlapping of physical properties and chemical composition. It is obvious, in Hokkaido, that they always occur in a fine grained massive state, and comparises several modification. Some members well crystallized but other a very poorly crystallized.
The writer found pyrolusite, manganite, cryptomelane, ramsdellite, birnessite and ranceite in Hokkaido. Ramsdellite has not been found in Japan, but it was found in fissure of Palaeozoic red chert from the Tanno mine, Kitami District in Hokkaido. Birnessite and ranceite are found in manganese wads from the Komagadake mine.
The manganese dioxide deposits in Hokkaido are found concordantly or slightly obliquely to the stratification in Miocene green tuff, tuff breccia, and shale. The modes of occurrence of many manganese dioxide deposits are controlled by geological structure : the deposits are distributed at special portion as small basin. A somewhat sedimentary cycle was given to explain the distribution of manganite → pyrolusite to upper bed from lower bed. These phenomena are applicable for the prospecting of the so-called Pirika type manganese dioxide deposits.
Some manganese oxide mineral specimens show under a rate heating, a characteristic type of differential thermal analysis curve. Natural manganese dioxide and hydroxide ores were aggregates of some manganese·minerals. The application of differential thermal analysis to this group of mineral provides valuable information invaluable by other standard method of technique.
In this paper, the results of mineralogical and geological distribution researches on these deposits are summarised.

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Sideritic Band (Ironstone) is located in the dark gray thin-bedded shale of the Horokabetsu Formation in the Ishikari Coal Field (Palaeogene-Tertiary in age), Hokkaido, Japan. Near the surface it is sometimes changed to limonite.
1) Occurrence : Sideritic band is pararelled to the stratification and formed as lenses, nodules, and beds ; having a thickness of 50 or 60 cm in maximum. The formation contains more than 10 seams.
2) Analysis : For example No. 2 : Total. Fe 26.26, FeO 33.23, SiO₂ 26.30, CaO 5.09, MgO 2.55, Ig. loss 26.30 wt % and Mol. %, as follows : FeCO₃=58%, CaCO₃=10%, MgCO₃=5%, Others=27%.
3) Microscopic observation : Essential mineral is siderite, and accessories are quartz, calcite, plagioclase, chlorite and pyrite, etc. In some section angular quartz is very common, plagioclase and chlorite are very rare. Carbonatization is strongly characterized.
4) Genesis : Siderite is a sedimentary origin as the products of calm sedimentation.
Iron is transported as ferric oxide hydrozol in the main. Then siderite is formed by diagenetic differentiation under moderately high Eh potential environment.

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In a place of the “Misumai-shale” of the Yakumo-series of upper Miocene near Sapporo, there is a gray, soft and muddy sedimentary facies enclosing calcareous nodules with iron sulphide minerals. the nodules are composed of crystals of iron sulphide and gray, coarser graind impure calcites. Minerals of iron sulphide are pyrite, marcacite and pyrrhotite, which are determined by the mineragraphic studies. These iron sulphides occur as forming thin crusts, disseminated grains and star-cloud like patches, or cube like metallic nuclei with curved surface in the nodules.
It is observed that there is a definite relation between the properties of iron sulphides and the modes of their occurrence, and not the shapes, nor sizes of nodules. Outer side of the crust and the nucleus are idiomophic pyrites, but inner side are composed of aggregates of fine pyrites and marcacites, or marcacites only. Pyrrhotites are found under the crust as single crystals showing hexagonal plates or prisms distributed inner part of nodules, or scattered in the nucleus of calcite or along the peripheral margins of it which recrystallized and purified from dark impure calcite.
It may be considered that during diagenetic processes iron sulphides crystallized from melnikovitic substances precipitated into muddy sediments in the sealed stagnant basin with clouds of calcareous micro-alges or micro-organisums. The most important influences affecting on composition of iron sulphides may be the available amounts of sulphur supplied mainly from out side of nodules as hydrogen sulphide, which is decomposed product of organic matter and included in bottom water and sediment ; namely sedimentary amorphous iron sulphides crystallised as pyrite (FeS₂), marcacite (FeS₂-x) or pyrrhotite (Fe₁+xS) in proportion to the provided available sulphur under lower Eh and higher pH environment.

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Temperature and frequency dependences of the dielectric constant and loss of a transparent single crystal of Brazilian quartz were measured for both directions parallel and perpendicular to its c-axis from -70° up to 600°C. and in the frequency range between 0.3 kc and 3 Mc by a C.R. bridge and a Q meter. Direct current electric conductivity was also measured from temperature up to 500°C. The enthalpy of activation for the dielectric relaxation was 21.3 kcal/mole and the activation energy for the d.c. conduction was 17.84 kcal/mole.
Infrared absorption spectra of the Brazilian quartz and a smoky quartz showed marked dichroism in the neighbourhood of O-H stretching vibration, 2.7-3μ in every case, but the absorption feature was distinctly different.
To compare these data with those for other silicate minerals, electric measurements were carried out for smoky quartz, vein-quartz, beryl and cordierite.
The most probable explanations for the molecular mechanism of such electric phenomena of quartz are deduced as follows :
1) Water molecules or OH ions and Na ions are trapped in some lattice defects being surrounded certain anisotropic crystalline fields.
2) When the temperature rised and an external electric field is applied, the water molecule can be orientated loosening the binding interactions due to O-H…O type hydrogen bonds and an ion-dipole interaction between Na-OH₂. This energy of activationis about 21 kcal/mole.
3) Just then the Na ion can be diffusible to the external field direction breaking away from the restriction. Therefore, the activation energy of diffusion is almost identical to that of the dielectric relaxation.
4) Direct current conduction does not necessarily imply long-range diffusion of ions, but may appear as the result of successive, relative displacement of ions in the lattice. This activation energy must be smaller than that of diffusion. It may correspond to the activation energy of d. c. conduction of about 18 kcal.

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Deweylite, a hydrous magnesium silicate, occurred from serpentine region in Horokanai-mura, Uryu-gun, Hokkaido, and it was yellowish or brownish colour and showed amorphous mass with small druses. Hardness: 2-3. Brittle and with small cracks. Fructure : Conchoidal. Translucent. Luster : vitreous or greasy. Under the microscope, it shows spherulitic texture or granular aggregates and shows amorphous state or weak birefringence. Indices of refraction are lower than 1.54. Decomposed by hydrochloric acid. Chemical analysis of the purified material follows : SiO₂ 41.62, TiO₂ none, Al₂O₃ 0.06, Fe₂O₃ 0.03, FeO 1.35, MnO trace, MgO 33.89, CaO 0.06, H2O (+) 17.60, H₂O (-) 6.13, total 100.74% (analysed by H. Minato in 1958). Spectroscopic analysis shows that its trace elements are Mn. Ti and Ni, and V, As, Sb, P, Cu, Zn, Cr and Co are not detected. Weight loss curve of the specimen by means of thermogravimetric analysis is given, also. X-ray powder pattern of the specimen agrees with that from Yagiyama, Fukuoka Prefecture and from Delaware, New York.

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The pegmatite in Teshirogi district has been studied by the writer since 1950. Recently the, writer found a characteristic brown colored mica in some pegmatite. From its chemical composition (K, Fe, Mg)₃ (Al, Si)₄ O₁₀ (OH, F). Mineral properties biaxial (-) 2V=12°, index of refraction. α=1.558. γ=1.601, pleachroism X=Yellowcolorless, Y=Yellowish brown, Z=Golden brown, X<Y<Z. It belongs to phlogopite clan. Therefore the writer proposed the name ferri-phlogopite for the mineral.

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The Kumano Mine is situated in Susa Town of Yamaguchi Prefecture, Japan. It is a contact metasomatic deposit of quartz-diorite with limestone. The primary ore is consisted mainly with magnetite, but suffering secondary oxidation or hydrous oxidation remarkably, almost all the ore is changed to maghemite and hematite with lepidocrocite and goethite. Taking up several specimens of maghemite showing various degree of deficiency, then heated at 300, 450, 600, 800 and 1000°c in air respectively. The heated products were studied by X-ray and chemical method, and referring the results of differential thermal analysis, the oxidation process of maghemite including magnetite is suggested as follows : 1. Genesis of vacancy in octahedral coordination position. 2. Movement of Fe³⁺ ions in tetrahedral coordination position to octahedral one, 3. change of lattice symmetry from cubic to rhombohedral. These three are concerned each other and at the end of oxidation, hematite only is recognizable. The higher the degree of defficieincy, the lower the temperature of the last exothermic peak shown in DTA curves.

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The Kamuikotan metamorphic complex develops as irregular long zone between the Mesozoic and Cenozoic formations along the western side of the Hidaka mountain ridge in Central Hokkaido. It runs about 200 km in a direction of nearly north to south, from areas of boundary of Teshio and Kitami Provinces to Hidaka Province.
In general the normal Kamuikotan complex is made up the products due to slight regional metamorphism, in which the chief petrological members are black siliceous schists and next comes an abundance of green schists, small amonnts of quartzite, phyllite, mylonite and crysrtalline limestone are intercalated in the complex. From the geological and petrographical points of view, it may reasonably be assumed that the Kamuikotan complex can be readily correlated with the Franciscan formation in California.
Comparatively large lenses or belts of the ultra-basic rocks run parallel with the trend of the Kamuikotan complex, being restricted mainly to the tectonic lines is the zone of the complex. It is noticeable that various interesting crystalline schists locally develop between the normal schistose rocks of the Kamuikotan complex and the ultra-basic intrusives, which have attracted special attention because of the presence of some special minerals, especially soda-bearing silicates. These special rocks may be a product brought about by contact metamorphic action due to ultra-basic intrusion and occurrence of the special minerals in them originated from pyrometasomatism, primarily owing to the action of some especially soda-rich hydrothermal solution drived from the ultra-basic intrusions.
The subject matter of this paper is an outline of these some special minerals in the pyro-metasomatized rocks, with special reference to the general properties of the following members ; (A) glaucophane and crossite, (B) riebeckite and crocidolite, (C) aegirine-augite, (D) stilpnomelane, (E) piedmontite, (F) garnet, (G) lawsonite, and (H) pumpellyite.

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Previous works on the structure and the polymorphism of micas were investigated, and many points in question arised. Authors determined the crystal structure of xanthophyllite, which was iso-structure with 1M type muscovite proposed by Pabst, 1955. Xanthophyllite has been formed only in twinned crystal as a whole. Hexagonal plates, consist of three or six pieces forming rotational twin, were multipled also vertically as a parallel growth or a polysynthetic twin. It was consequently found that they had pseudo-hexagonal symmetry in structure too, lattice points of one of twin was superposed by those of other, so that the optical anormal property of the mineral had been caused to misconceive twin for single one. Most of twinned xanthophyllite were holding c-axis in common. From the fact above mentioned, authors assumed as follows, for the occurrence and the growing mechanism of xanthophyllite: First, a single crystal of a hexagonal plate, in which (Si, Al)O₄ double sheets superposed vertically, crystallized. In the cause of the cooling of the crystal, the double sheets translated gradually to low form from each side of the hexagonal prism. For these reason, it was concluded that most of mica polymorph of previous works had been apparent one. It was also discussed that cleavage planes of micas were only platy joints resulting of contraction along c-axis at the period of the transition.

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In order to select the most suitable working conditions of qualitative spectrographic analysis of sulphide ore minerals for minor constituents, the following several fundamental experiments were performed with each specimen of both sphalerite and pyrite, using a Shimadzu NQM60 Type Quartz medinm spectrograph.
The working conditions discussed in the present study are as follows : (1) Excitation method (comparison of comparative sensitivities for anode and cathode layer excitation), (2) Gap (varied 2 to 4 mm), (3) Current (varied 4 to 8A-110V, DC), (4) Time, (5) Depth of crater (varied 1.5 to 3.0 mm.).

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The Shimokawa mine, which is in about 7 km. SE of the town of Shimokawa, is noted as the only working large deposit of cupriferous iron sulphide ore in Hokkaido.
The ore deposits of this mine are formed in the shear zone along the eastern margin of a diabase slate complex mass, and in it cupriferous pyrite deposits have replaced the diabase and slate both. The ore deposits belong in the category of so-called Kieslager.
The ore is composed mainly of pyrite and chalcopyrite, with a small amount of pyrrhotite, sphalerite, cubanite and galena, but it is divided into compact ore and impregnated or banded ore. For these experiments, the samples of sphalerite were taken from the compact ore.
The samples are arranged firstly according to the Ostwald colour standards. Next, the composition of every colour may be represented by an equation of the form C+W+B=100%, where C=Full Colour, W =White, and B=Black. In this manner, the relations between hue and brilliance are determined.
Regarding the relations between colour and content of iron, the former shows dark in accordance with increase of the latter. Besides there is a tendency among sphalerites to be more pale in colour than dark in regard to the contents of minor elements.
If one notes carefully minor elements in tables 2 and 3, he will note that there are Fe, Pb and Cu in wide area, but Co, Ni, and Mn in partial one relatively plentifully. Besides, it is shown, that Ag, Sn and Pb are in the central part of the ore body, Bi, Te, and Ga are in the margin, but that Cs and In are in a restricted part.

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The author reported the results of the chemical compositions, the optical properties, and the differential thermal analysis curves, and determined the structural types of three specimens of mica group mineral.
The chemical formula and the structural type of hydrous muscovite, which was found in muscovite vein in serpentine rock from Maruo, Ube City, Yamaguchi Pref., Japan, are as follows :
(K_0.63Na_0.12Ca_0.02 (H₃O)_0.29)_1.06 (Al_2.08Ti_0.01Fe''_0.01Fe'''_0.07Mg_0.05)_2.22 (Al_1.11Si_2.89)_4.00O₁₀(OH)_2.00· Structural type ; 2M₁, a=5.19Å, b=8.99Å, c=20.09Å, β=95°30'.
The chemical formula and the structural type of muscovite, which was found in “Roseki” deposit embedded in liparite from the Uku Mine, Yamaguchi Pref., Japan, are as follows:
(K_0.69Na_0.13Ca_0.02 (H₂O)_0.15)0.99 (Al_2.05 Fe'''_0.03 Mg_0.08)_2.16 (Al_1.16 Si_2.84)_4.00O₁₀ (OH)_2.00 Structural-type ; 2M₁, a=5.18Å, b=9.00Å, c=20.18Å, β=95°K20'.
The chemical formula and the structural type of biotitic phlogopite, which was found in cavity in basalt from Mutsure Island, Yamaguchi Pref., Japan, are as follows : (K_0.82 Na_0.31 Ca_0.01)_1.14 (Mg_2.16 Fe''_0.46 Fe'''_0.18 Mn_0.01 Ti_0.20)_3.01 (Al_0.89 Si_2.97)_3.86 O₁₀(OH_1.48 F_0.07)1.55·
Structural type ; Monoclinic three-layer structure (“3M”).
a=5.30Å, c=9.24Å, C=30.56Å, β=90°30'.
The author discussed the relationship between the conditions of its formation and the structural types on the basis of the above mentioned three mica and previously reported data.

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Zircon is one of the most common and familiar minerals which are distributed widely in various rocks. Therefore the mineralogical characters of zircon have attracted the interest of geologists, petrologists and mineralogists and have been investigated from various stand points of geology. Some of these characters are very intimately related to the content of radioactive elements, and this investigation was made as an attempt to account for these relationships.
The uranium contents of representative zircon specimens collected from the weathered granite sands of the Tensi Mine were analyzed by the microfluorimetric method. To eliminate the quenching effect of fluorescence intensity derived from the bluk zirconium, the actual contents were calibrated by multiplying the coefficient 1.31 to the apparent value determined by the direct method.
The radioactivity of zircon was measured by the decatron type countmeter, and it was generally proportional to the uranium content. The natural fluorescence intensity activated by the ultraviolet ray was determined by means of the sensitive photomultiplier detector, and the fluorescence intensity of zircon containing a comparatively large uranium was lower than that containing smaller amount.
An attempt to find some relation between the colour and the uranium content in zircon was fruitless except for the facts that the colorless zircon was relatively low in its radioactivity but that the greenish brown member was moderately high. The lattice defect of zircon was also investigated with the Geiger counter diffractometer and related to the uranium content.
Various minor elements contained in zircon were semiquantitatively determined by spectrographic method.
From the above experimental results, the intrusion of granite batholith was classified into three following stages, first the stage in which the first intrusion of granite represents the northern part of this district and the zircon content in granite is rich and the uranium content in zircon is small, and secondly the stage in which the second intrusion of granite represents the southern part and the zircon content is small and the uranium content is slightly richer than that of the granite found in the northern part, and finally the stage in which the third intrusion of granite represents the middle part and the zircon content is of moderate amount but the uranium content ranges from a small to a large amount.

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Cristobalite and opal are contained in the wall-rocks (tuff and agglomerate) of the native sulphur and iron sulphides ore deposits, and in the disseminated limonite (goethite) ore of the Abuta Mine in south-western Hokkaido, Japan.
These are not found in the massive iron sulphides ore and moss-limonite (goethite) ore that always contains quartz as silica minerals. The x-ray diffraction data show that the cristobalite is mostly α-(low) type. Its hexagonal platy crystal can be found in the electromicrograph.
It is considered that the cristobalite has been formed as a secondary mineral from opal which is one of the hydrothermal alteration minerals-alunite, kaolin, montmorillonite, anatase?, pyrite, marcasite, native sulphur, etc. Cristobalite is also found in the wall-rocks of the native sulphur ore deposits of the Tokusyumbetu Mine and in the clay under the moss-limonite (goethite) ore deposit of the Kuttyan Mine.

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In the course of the study of ores of skarn type found in some dolomite granite contact aureoles, the writer discovered several new occurrences of magnesium-borate minerals such as kotoite, suanite, ludwigite, paigeite, warwickite, szaibelyite, etc. in Japan and Korea.
The magnesium-borate minerals usually occur at close to contact of granitic rocks with dolomites as boron metasomatic products.
The paragenesis of the borate minerals of many localities are briefly summarized. Genesis of the boron bearing minerals in the contact aureoles are discussed.

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The pyroxenes of the acmitte-diopside system, which shows a complete solid solution relation, have been synthesized by sintering the glasses of the corresponding compositions. Their optical properties (refractive indices, axial angles, and extinction angles) are determined, and a new diagram is presented to show the relation between these properties and the chemical compositions. The diagram is examined by comparing with numerous natural alkalic pyroxenes, and is proved to be useful for determinative purpose.
Of the unit cell dimensions determined from the diffraction patterns, β, ao, and bo show decrease with increasing acmite molecules, while co remains more or less constant.

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Short prismatic crystals of common augite 3-1.5 mm across have been found as the phenocrysts in Pliocene volcanic tuff from Neppu, Siribesi Prov. Hokkaido. Observed forms are : a (100), m (110), b (010), c (001), s (111) with small z(021).

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Coquimbite was found from an old adit of a Au-Ag vein of Konomai mine, Hokkaido associated with a few hydrous sulphate minerals. The colour varies from whitish purple, purple to reddish purple. The crystal displays hexagonal platy on prismatic form composed of c (0001) and m (10I0) with rare small faces a (1120) and r (10I1). It was identified with the lights of chemical analysis and X-ray study.

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Voltaite from the same locality grows on coquimbite as small black crystals with o (111) and a (100) as principal faces. and d (110). The identification was based on the optical character (n= 1.600), chemical analysis and X-ray study.

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Roemerite from the same locality forms an aggregate of small chest nut brown platy crystals. The identification was also based on the chemical and X-ray characters.

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Xenotime from Takehara, Mie Prefecture was found in granite pegmatite associated with monazite and zircon.
There are some varieties in colour and crystal form.
1. Bluish gray pyramidal crystal of z (101) as principal face with a (100) and l (121). Parallel growth with zircon is usually.
2. Dark gray one occurring in radial aggregate.
3. Grayish green one composed of aggregate of grain. Rarely, shows pyramidal crystal with z (101). It was identified by X-ray, powder data.

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Monazite from Takehara, Mie Prefecture is greenish gray brown prismatic or platy crystal with a (100), m (110), v (I11) as principal faces, and sometimes with n (120), e (011), w (101) and x (I01).
Fergusonite from same locality is blackish small loose crystal, and sometimes as prismatic one with s (111) and g (320).

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