In the Cs-lepidolites, there is a wide range of chemical heterogeneity involving the multisite substitutions ^[6]Li_-1^[4]Si_-1^[6]Al^[4]Al and F^-_-1(OH/OD)^-. Short-range order occurred during rapid crystal growth due to local charge-balance effects in each mica.

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Laihunite, laihunite-2M, and triple period superstructure of laihunite occur from a pegmatite from Crystal Park, Colorado. The triple period superstructure of laihunite consist of three modules where vacancies of F2 site occur at Z=0, Z=1/2, and Z=1, respectively. The triple period superstructure differs from laihunite-3M where a unit cell of fayalite is sandwiched by two laihunite unit cells.  

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Quartz samples from obira mine, oita prefecture,
Japan, show a characteristic internal texture. we observed the texture by using optical
microscopy, CL and EBSD methods. From the results, we will discuss the
formation process of the texture.

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Trace titanium contents in fluid inclusions from a miarolitic cavity's quartz at the Tsushima granite, Japan, were analyzed byparticle-induced X-ray emission (PIXE) to examine behaviors of Ti in granite-derived hydrothermal fluids in granite bodies.

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Natroapophyllite, NaCa₄Si₈O₂₀F・8H₂O, was found in aggregate of borate minerals such as shimazakiite at the Fuka mine, Okayama, Japan. Natroapophyllite was first discovered from the Sampo mine, Okayama, Japan. This mineral is reported as a new mineral with structural analysis by Matsueda et al. (1981). The chemistry of natroapophyllite from Fuka is characterized to include small amounts of Mg, Fe, Mn and B. The unit cell parameters are a=8.939(11), b=8.959(18), c=15.785(9) Å, and V=1264(7)ų.

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Aggregate crystal zeolites are occurred in the boninite pillow lava and pillow breccia at Chichijima and Anijima, the Ogasawara Islands. At the localities in this study, heulandite/clinoptilolite, chabazite, stilbite, phillipsite and mordenite zeolites having the higher-silica composition are occurred co-existed with calcite, quartz/chalcedony and celadonite. Almost of the heulandite-like habit crystals sampled in the localities are identified as clinoptilolite in the base of IMA nomenclature.

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Na-rich garronite was found in basaltic rock with epistilbite and chabazite-Ca in Hirado Island. Ideal chemical formula of the garronite is shown as NaCa_2.5(Al₆Si₁₀)O₃₂ 14H₂O. Though the Na/(Na+Ca) molar of garronite generally is shown a range of 0.05 to 0.37, the Na-rich garronite is 0.49 to 0.60. The unit cell parameters, a=9.975(7) Ǻ, b=10.178(1), c=9.945(2), beta=89.977(1)° and V=1009.6(7)Ǻ³, are slightly larger in a axis, and smaller in c axis than those of garronite from Oki Island.

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Xonotlite have been found in the Yatani mine, Yagamata Prefecture, Japan. Samples bearing xonotlite
were collected in the Higashi Tengu No. 2 vein. This mineral shows white massive aggregate, composed of fine fibrous crystals less than 200 μm, and coexists with johannsenite, calcite and quartz. The XRD pattern of the mineral corresponds to xonotlite of PDF 23-0125. The empirical
formula of xonotlite obtained by WDS is (Ca_5.91Mn_0.06)_Σ5.97Si_6.03O₁₇(OH)₂ (O = 19, OH = 2apfu).

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Anilite, Cu₇S₄ is found at quartz-epidote lens in albite spotted shist from Sanbagawa Metamorphic Zone, Ochikata, Kinokawa City, Wakayama Prefecture, Japan. The mineral occurs as platy or indeterminate forms crystal up to 3 mm in size in the quartz lens with native gold and covellite. The color is bluish gray and its luster is metallic. The empirical formula is Cu_6.99S_4.01.

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Kalgoorlieite is a new mineral which was approved by IMA on February to March 2016. In this time, kalgoorlieite was found from Teine mine, Hokkaido prefecture, Japan. Kalgoorlieite of Teine mine shows anhedral to subhedral crystal up to around 200 micro meter which occurs in quartz, often coexistent with native tellurium and tellurides (e.g. stutzite, altaite and coloradite).

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Epidote-(Sr) is new mineral which was reported by Minakawa et al. (2008). In this time, epidote-(Sr) was found from Shiromaru mine, Tokyo prefecture, Japan when Shiromaru dam discharged water in 2016. Epidote-(Sr) from Shiromaru mine occurs as vein cut a reddish chert which contains hematite. The occurrence is similar to Ananai mine. It is considered that the vain was formed by last stage hydrothermal effect after formation of Manganese deposit.

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Austinite occured from the Kitabira mine, Yamaguchi Prefecture, and this is the first occurrence from Japan. The unit cell parameters of austinite near the end member are a = 7.483(4), b = 9.039(6), c = 5.920(4) and V = 400.4(3). The chemical zoning in spherical aggregates is significant. They have values of Zn/(Zn+Cu) = 0.21-0.91 and As/(As+P) = 0.82-0.97. The chemical composition of austinite near the end member is (Ca_0.97Cd_0.01)_Σ0.98(Zn_0.86 Cu_0.11)_Σ0.97(As_0.97P_0.05)_Σ1.02O₄(OH).

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Mn rich tourmaline with Li rich tourmaline occur from Sakihama pegmatite, Iwate Prefecture. The dark green part of tourmlaine crystal is tsilaisite. Light green, colorless and pink parts are fuluorelbaite, and light blue part is elbaite. Fine fibrous foiteite is formed on surface of the crystal. The chemical composition of tsilaisite from Sakihama is (Na_0.58Vacancy_0.41Ca_0.01)(Mn_1.02Fe_0.20Zn_0.02Al_1.19Li_0.57)Al₆(Si_5.80Al_0.20)O₁₈(BO₃)₃(OH)₃(OH_0.65 F_0.35).

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Robertsite with blak Mn-minerals occur from Nagatare pegmatite, Fukuoka Prefecture, and this is a first occurrence from Japan. The chemical composition of robertsite is (Ca_1.80Mn²⁺_0.20)_Σ2.00(Mn³⁺_2.79 Fe³⁺_0.20)_Σ2.99O₂P_3.00O₁₂·3H₂O. Mn and Fe has negative correlation. Unit cell parameters are a = 17.36(1), b = 19.50(1), c = 11.313(9), β = 96.65(8) and V = 3804(4). However, some weak reflections indicate a possibility of containing pararobertsite.

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Cheralite was found with Lepidolite, Albite, Quartz and Columbite-(Mn) at Nagatare mine, Fukuoka Prefecture, Japan. The compositions of Cheralite is (Ca_0.82, Th_0.82, Sm_0.13, Gd_0.12, U_0.06, Ce_0.04, Nd_0.04)_Σ2.03(P_1.87, Si_0.08)_Σ1.95O₈. The unit-cell parameters are a = 6.724(9), b = 6.937(5), c = 6.445(7), β = 103.9(1), V = 291.8(4).

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Total 53 out of 117 structures of apatite-type compounds hitherto published were examined in view of the relationships among position of X anion (0 0 z) and sizes of A(2)₃ (at z = 1/4) and O(3)₃ (at z ≈ 0) triangles which compose an X anion channel along the c axis. In general X anion is most stable at z = 0 as far as the O(3)₃ triangle is large, and moves to the center of A(2)₃ triangle when the O(3)₆ trigonal antiprism is small and repulsive force from those oxide ions is unignorable.

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Hydropyroxenoids with 3-periodic single-chains of SiO₄, simplified formula (Li, Na)(Ca, Mn)₂[Si₃O₈(OH)], from five localities were studied to examine the relation between Li-Na substitution and H-bond system. The substitution of smaller Li⁺ ion for Na⁺ gives an influence on the geometry polyhedra, and changes the bond valence sums of neighboring oxygens and hydrogen bonding system.

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The 4H=1Si substitution is well known for hydrogrossular, and has also been suggested for other mantle minerals, such as olivine. The inference was mostly based on infrared spectra, but the interpretation is not unambiguous. Here we apply NMR spectroscopy, in combination with first-principles calculation to shed better light on this issue. We compare the proton distributions in hydrogrossular and forsterite, demonstrating that they have similar, but not identical configurations.  

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The crystal structure refinement of parasymplesite from Kiura mine, Ohita, Fe₃(AsO₄)₂8H₂O converged into R = 0.0304 and S = 1.154 for 722 independent reflections of single-crystal XRD data. The hydrogen bonds were described based on hydrogen atom positions on the difference Fourier maps in reference to the bond valence calculations. The bond distance of M2-O5, where O5 is the oxygen of H2O groups, is shorter than that of M2-O2, the oxygen atoms of edge-sharing M22O6(H2O)4 double octahedra. 

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The devil’s flower is an peculiar phase diagram obtained from ANNNI model. It already found in spin, lattice, and charge system, then we explored it in dipole moment system. We assume permanent dipole of chains of molecules in crystal as spin, we obtained each energy of nearest and next nearest neighbor via DFT calculation with semi empirical dispersion force correction. From calculation result, modulated structures that have long period will appear around 750 MPa.

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High pressure phases of ice can be classified into some pairs which contain dis ordered phase and ordered phase with positions of oxygen atoms in ice. Generally, an ice structure of dis ordered phase has many corresponding ordered structures obeying ice rule. In this presentation, I’m going to talk about a symmetry-classifying method of these ordered structures.

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High temperature in situ single crystal X-ray diffraction experiments on hauyne of two localities were examined by using an imaging plate type X-ray diffractmeter with a horseshoe-shaped Pt heater. Observation of the satellite peaks, determination of cell parameter and measurement of diffracted intensity were performed at eight points between 20˚C and 700˚C. Oscillation photographs of Italy sample showed no satellite reflection. 

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The relative occurrence frequency of the three know twins in olivine appears contradictory with the degree of quasi-restoration of the crystallographic orbits and call for a re-examination of the assigned twin laws.

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There are 7 dense homogeneous packings of ellipses, with N=6,(contacting neigbours). Among them, 2 types( p2 1a2 and c2mm 2a 2mm)attain
the maxmum density ρmax,π/√12,being the same of circle p6mm,1 a 6mm.
Other 5 types [p3 3d1,p31m 3cm, p2gg 2a2, p2gg4c1(I), p2gg4c1(II)] cannot exceed ρmax. Thus Matsumoto-Nowacki hypothesis is effective to ellipses packings.  
We can also consider the extension  pattern of  heterogeneous packings from  the p2gg-4c1(b) packing.

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Ordering and phase separation of non-ideal solid solution are studied by an exchange reaction model between solid and
vapor. Monte Carlo simulation is also used to obtain the data for comparingwith theoretical results. The theoretical model by using the pair-approximation well-explains the MC results.

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The dehydration kinetics of diaspore was investigated by a thermal gravimetric technique under both isothermal and non-isothermal conditions. The non-isothermal kinetic data were analyzed using the model-free isoconversional method. The mechanism of the dehydration process will be discussed from the activation energy of the dehydration process obtained.

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Si-Al hydrous amorphous materials are major initial product of weathering. Crystallization process from Si-Al hydrous amorphous materials and its kinetics are important for quantitative analysis of terrestrial environment. In this study, hydrothermal experiments of synthesized Si-Al hydrous gel were carried out. Main crystalline product is acicular aggregates of kaolinite.

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The local structure around Ge in alkali germanate glasses was investigated using AXS and EXAFS measurements. Structural changes accompanying the so–called germanate anomaly will be discussed.

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The structure of diatom frustule was transformed to opal-CT just after compression under 100 ^oC without the morphological change, and then its structure and morphology were retained at least up to 6.9 GPa. With keeping the compression of 5.7 GPa under 100 ^oC for 7 days, the structure was changed to coesite. After 7 days under 0.3 GPa and 100 ^oC, the structure of diatom frustule was changed to a mixture of a-moganite and a-quartz, which was an approximately similar texture to chalcedony.

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Wehave carried out experiments of low-quartz (SiO₂) using CaO-Na₂O-B₂O₃-Li₂O-V₂O₅ flux, and have succeeded in growing hexagonal prismatic quartz crystals with pyramidal faces at each end in experiments at temperatures heated up to 660 and cooled down to 555ºC. In addition, low quartz crystals, although small, were obtained in the experiments at temperatures heated up to 570ºC, within the low quartz field. In order to improve the crystal size, a quartz and cristobalite mixture was used.

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The coordination environments of Ti in K-Pg boundary clays were studied by K-edge XAFS. The XANES spectra and Ti-O distance of K-Pg clays are similar to those of suevite. The formation information at meteorite impact is preserved in the coordination environments of Ti in K-Pg clays. The similarity between Ti coordination environment in K-Pg clays and that in impact glasses suggests that Ti coordination environment investigation may be exploited as a marker of large meteorite impact. 

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We have conducted variable-temperature single-crystal X-ray diffraction studies of NaSr₂Mg₂V₃O₁₂ and Na₃Sc₂V₃O₁₂, in order to examine the reason for the peculiar atomic displacement behavior of tetrahedral V ions observed in some vanadate garnets. The results led to the conclusion that the peculiar atomic displacement behavior is due to the static disorders of V ions in the [100] direction.

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Crystal structure of iridescent garnet from Tenkawa village, Nara prefecture, Japan was investigated in order to discuss the origin of cation ordering and lamellae texture. Result of the refinement with the space group I-1, the Fe3+ occupancies of the eight Y sites in the {110}c sector were refined as follows; 89.2(6), 97.8(6), 93.0(6), 99.6(6)%,, 96.8(6), 93.1(6), 95.7(6) and 100.3(6).

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High temperature single-crystal X-ray diffraction study of a synthetic PbTiO3 perovskite was carried out in the wide temperature range. The Pb contributes sufficiently to polarization as well as Ti because the positions of both cations shift to the opposite direction of O positions. The deviation from the linear changes in Debye Waller factors and bonding distances in the tetragonal phases can be interpreted as a precursor phenomenon before the phase transition.

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We discovered a novel feature of Mackinawite that is capable of charging electron, which was observed in both biogeneic and chemically synthetic Mackinawites. Machinawite was analyzed to elucidate the charging mechanism by using material scientific techniques. Unexpectedly, Mackinawite was transformed to Lepidocrocite after discharge. A part of Lepidocrocite was transformed to Mackinawite after charge.  These results indicated that the Mackinawite and Lepidocrocite transform reversibly.

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The structures of boehmite and lepidocrocite has not been determined. It is said that these minerals have several candidate in space group and the position of hydrogen atoms is only different. Therefore, there is room of symmetry and the hydrogen’s position of boehmite and lepidocrocite. 
Rietveld refinements on the neutron diffraction patterns were conducted on the basis of disorder phase and order phase. The residual of fit of disorder phase was slightly less than that of order phase.

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Russellite (Bi₂O₂) occurs as a pale yellow-green pellet in nature. It crystallizes in orthorhombic, Pca2₁, a = 5.434(2) Å, b = 16.432(2) Å, c = 5.455(2) Å. We examined structure of synthetic russellite in detail, before and after HCl treatment, with single-crystal XRD and IR and Raman spectroscopies. Rsults of both XRD and Raman spectroscopy indicated release of structural strain by H⁺-intercalation in the structure.

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The crystal structure refinement of clinoclase from Ikuchi, Hiroshima Cu₃AsO₄(OH)₃ converged into R = 0.0245 and S = 1.158 for 1598 independent reflections of single-crystal XRD data. Space between the respective complex sheets is filled with hydrogen. Two kinds of five coordinate Cu-sites form largely distorted tetragonal pyramids. The four coordinate Cu-site forms square planar. We will discuss the complex structure and largely distorted Cu-sites, Van der Waals bonds and hydrogen bonds.

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Single crystal X-ray diffraction experiments for diaspore have been worked in the temperature range from 22 to 425 ºC, in order to understand detailed mechanism of thermal expansion. Temperature variations of the cell parameters indicate that thermal expansion of the a-axis is higher than that of the b-axis or the c-axis. The results of the structure refinement suggest such anisotropic behavioris due to thermal expansion of the empty cavities in the structure of diaspore.

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This study reports the result of structural study on a variety of natural apatite samples, which allows us to demonstrate the structural feature of apatite and to discuss the structural behavior of REEs of phosphors with the apatite structure.

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Plagioclase is a major constituent mineral in the Earth's crust .We prepared the samples of polycrystalline labradorite and measured compressional wave velocities (Vp) and shear (Vs) wave velocities. Ultrasonic measurements on these samples were conducted up to 1.0 GPa in a temperature range of 25-450°C in a piston cylinder apparatus.

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In this study, the adsorption rate in the inorganic porous material was measured and a relation between the size of the pore and the rate was considered. Adsorption rate was calculated from water vapor absorbed amount measurement every each time. As a result, there was 2.5 times as much absorbed amount of silica gel as absorbed amount of zeolite in adsorption for 4 hours, but zeolite was with 1.3 times of the silica gel for the adsorption rate by the adsorption time for 5 minutes.

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Syntheses of spinel werre performed by flux method. Starting materials are as follows. The principal ingredients are MgO and Al₂O₃. The coloring reagent is Cr₂O_3. The fluxes are PbO and PbF₂. The results are reported.

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Fine-grained polycrystalline diopside and polycrystalline salite were prepared from nano-sized clinopyroxene powders. Clinopyroxene powders fabricated from two types of clinopyroxene single crystal (diopside, salite) are sintered under argon flow at temperatures of 1130-1280 deg C for 2-6h. As a result, high density polycrystalline diopside and polycrystalline salite with an average grain size of <500nm are obtained at a sintering temperature of 1180 deg C and 1130 deg C, respectively.

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Ice crystal structures are treated as graphs, consisting of vartices of oxygen and edges of O-H...O bonds, and characterize ice polymorphs.

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Structural change of glass sponge by heat treatment was investigated by IR spectra measurements. Glass sponge kept non crystalline structure even after heat treatment up to 900°C. IR spectra of heat treated sample indicated that molecular water and OH disappeared at 600°C, and IR band at ν≈790cm^-1 shifted toward higher wavenumber up to 600°C. It is assume that dehydration of water molecules and silanols affect medium range structure of the SiO₄ network.

 

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Structural change of ground alkali-feldspar (Or₇₇Ab₂₃) glass was investigated by XRD analysis and FTIR Raman spectroscopy. The samples became to show high density and high angle of FSDP with increase grinding. These two values showed linear relations each other.
This relation is similar to the grinding of SiO₂ glass and albite glass. The densification by grinding of two alkali-feldspar glasses were smaller than that of quartz glass and influenced by the size of cation in
alkali-feldspar.

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Amorphous calcium carbonate (ACC) is a metastable form of CaCO₃ nH₂O.
This study demonstrates the crystallization behavior of ACC with respect to the synthetic conditions. The disordered structure of ACC is also discussed by means of high resolution PDF analysis.

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X-shaped Japan-law twins of quartz from two localities in Japan, i.e., Oshigahae, Miyazaki Prefecture and Mitsuiwa, Gunma Prefecture, were analyzed by cathodoluminescence and EBSD. It was revealed that all of the examined samples evolved from a single center and developed as penetration twins. This formation mechanism is in contrast to the previously believed mechanism, which considers the X-shaped twins as a result of a combination of two y-shaped twins.

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The deformation micro-textures of MgO single crystals shock-compressed along the different orientations were observed under TEM to examine the different behaviors of deformation depending on the compression of the different orientations. The sample shock-compressed along <100> demonstrated only the {110}<110> slip system of dislocations, while the sample shocked along <110> displayed the {100}<110> slip system in addition to {110}<110>.

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