We obtained high-resolution X-ray CT images of the submicron scale plagioclase dendrites at SPring-8 BL47XU. The samples are lava fragments collected at the impact crater created by the vulcanian explosion of the Shinmoedake volcano on 1^st February, 2011. The dendrite branch spacing of plagioclase was ca. 500 nm. The pyroxenes and Fe-Ti oxides of <10 μm were also imaged. It was revealed that the three dimensional morphology of these plagioclase crystals were more complex than expected from the observation of a cross section. The growth of groundmass crystals might have continued after the emplacement of the volcanic bomb.

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Daugter minerals in polyphase inclusions of quartz crystals from a miarolitic cavity and quartz veins at the Tsushima granite, Japan, were analyzed with Raman microscopy to examine chemistries of hydrothermal fluids from the Miocene granite body. Small crystals of siderite, ferropyrosmalite, and iron hydroxide-like phase were detected in the inclusions.

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We report the mineralogical features of clay minerals from Nagatare Li pegmatite, and discuss the alteration processes. In Nagatare, Li pegmatite has veined structure, and clay-like minerals occur as red, pink, light blue and white masses or powders with Li minerals. Red clays were composed of K-Ca montmorillonite or cooketite with quartz. Pink clays were composed of K-beidellite, tosudite, cookeite and quartz. Light blue clays were composed of tosudite, cookeite and quartz. Tosudite was mixed layer minerals of
cookeite and Ca beidellite (or montmorillonite) layers. Various alteration reactions occurred with different formation temperature and composition of reaction fluid.

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There are many carbonate veins in serpentinite at Furuyasiki, Fukuoka Prefecture, Japan. In veins, hydrotalcite group minerals occur, which are purple, white and brown. In this research, we mainly analyzed the purple one, and stichtite from Dundas, Tasmania, Australia for comparison. Purple hydrotalcite group mineral from Furuyasiki is stichtite, and occurs as plates around chromite in serpentinite, which is contained in dolomite veins. As a result of the analysis, formulae of stichtite were Mg_6.09(Cr_1.55Fe_0.39)CO₃(OH)₁₆ 4H₂O (Furuyasiki) and Mg_6.07(Cr_1.17Fe_0.62Al_0.07Si_0.06)CO₃(OH)₁₆ 4H₂O  (Dundas). From X ray diffraction pattern, stichtite from Furuyasiki had 3R polytype.

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Kurchatovite, Ca(Mg, Mn, Fe)B₂O₅, was found in aggregate of borate minerals consist mainly composed of shimazakiite at the Fuka mine, Okayama, Japan. Kurchatovite was first described as a new mineral by Malinko et al. (1966) from Solongo, Siberia, Russia. This is the first report of kurchatovite in Japan. The chemical composition range of kurchatovite from Fuka showed from the near Mg end-member to the middle member of Mg and Fe. But Mn is almost no included. In this range, kurchatovite is formed a continuous solid solution. The unit cell parameters are a=36.29(3), b=11.14(1), c=5.497(4) Å.

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A Mn-Co arsenate mineral is found from the Takanosu mine, Tochigi prefecture. This mineral seems to be manganohoernesite. 

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The occurrence, optical properties and morphology of the "cordierite" from Sakkabira was described by Morimoto and Minato (1949). Miyashiro (1956) noticed that the mineral is distinct from cordierite and described it as a new mineral osumilite. On the other hand, we discovered that some type of "osumilite" is actually a Fe-rich variant of cordierite, i.e., sekaninite. While modes of occurrence of osumilite and sekaninite are exactly the same, sekaninite exhibits simpler crystal morphology formed by pseudo-hexagonal {100} and {001} faces, and it is almost always covered with brownish-red iron-oxide or -hydroxide.

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Poppiite, the V end-member of the pumpellyite group mineral is found at manganese ore deposit from the Yamato Mine, Kagoshima Prefecture. The mineral occurs as thin veinlets cutting Kutnohorite - Pyroxmangite manganese ore. Poppiite is the first occurrence in Japan. The empirical formula is (Ca_1.60Mn_0.28Na_0.11)_Σ1.99(V_0.72Fe_0.14Mg_0.11)_Σ0.97(V_1.99Al_0.01)_Σ2.00
(Si_3.02Ti_0.01)_Σ3.03O_10.64(OH)_3.36. XRD data are : a = 19.274(7), b = 6.052(2), c = 8.883(2) Å, β= 97.34(3)°, V = 1027.7(7) ų, seven strongest XRD lines [d in Å (I)] are : 3.820(75), 2.935(100), 2.752(60), 2.658(65), 2.556(60), 2.205(45), 1.617(60).

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Bismuth, bismuthinite, ikunolite, joseite A, joseite B and kobellite as Bi-bearing minerals occur in association with chalcopyrite, pyrrhotite, and gold in quartz veins cutting quartz porphyry at the Jishakuyama ore deposit of the Akagane mine, Oshu City, Iwate Prefecture, Japan. Among them kobellite is the first occurrence in Japan. Also cannonite and bismite are found as secondary minerals.

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A Pb-Bi-Se-S mineral, is found from Oohinata region, Minami-saku-gun, Nagano Prefecture. It seems to be cannizzarite or weibullite resulting from XRD method.

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We found a new mineral, bunnoite, and thus the detail is reported here.

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Abuite is a new mineral found in hydrothermally altered rocks in the Hinomaru-Nago mine, Kiyo area, Abu, Abu County, Yamaguchi Prefecture, Japan. Abuite is transparent, 100-500µm in size, embedded with quartz and augelite and/or trolleite, and is sometimes accompanied by apatite and crandallite. The empirical formula (based on 10 anions pfu, O =8, F+OH = 2) is (Ca_0.99Sr_0.01)_1.00Al_1.96P_2.03O₈(F_1.89OH_0.11). The simplified formula is CaAl₂(PO₄)₂F₂. Unit cell parameters are a = 11.818(2), b = 11.993(3), c = 4.6872(8) in an orthorhombic cell.

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The polarized infrared spectra of H-bearing monazite (LaPO₄) was observed to obtain information on OH defects in the crystal lattice of monazite. Two OH absorption bands were observed at 3164 cm^-1 and 3330 cm^-1. Based on the results from polarized FT-IR observations, these bands showed an anisotropic absorption parallel to [110]. 

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We report here new experimental kinetic data on the graphitization in a wide range of temperature conditions (1000 and 1450 °C) and time (10 min to 115 hrs) under a pressure condition of 1GPa. The crystallinity of natural CM, extracted from sedimentary rocks in the Shimanto accretionary complex and Hidaka metamorphic belt, transformed to fully ordered graphite, suggesting the Arrhenian relation between temperature and time. On the basis of experimental data, we obtained the effective activation energies of 274 to 334 kJmol^-1 and it is expected that natural graphitization process can easily be represented in a geological time-temperature relation.

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It was found that a larger amount of Se(VI) than Se(IV) was incorporated from adsorption site on the surface into the barite crystal by substituting sulfate site because of their high crystallinity that can excludes Se(IV) to a larger degree than Se(VI) due to the similar structure of sulfate ion and sulfate.

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Grain growth experiments were performed in sintered polycrystalline diopside. Powders of crushed natural diopside were sintered at temperatures between 1230 - 1280 deg C for 1 - 12h. The grain size increases with increasing time and temperature. At 1230 deg C, we observed normal grain growth characterized by a log-normal grain size distribution following the relation, D_f ⁿ ‒ D₀ ⁿ = kt where n is a constant, D_f and D⁰ are the grain size at time t = t and t = 0 respectively, and k is a rate constant.

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A general expression of normal growth rates of planner interfaces of minerals is obtained by two following considerations; (1) dependency of normal growth rate on the interspacing of growth interfaces and (2) thermodynamic expression of growth systems.

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Grain growth of ice plays an important role for understanding the mechanism of deformation and flow. In this study, we focused attention on NaCl solution which is a typical impurity in surface water of earth. Polycrystalline ice samples formed at –25 °C or –30 °C were annealed at every 5 °C from –20 °C to –5 °C. In pure water system, no significant grain growth was observed between –25 °C to –15 °C, and noticeable grain growth suggesting abnormal grain growth was observed between –10 °C to –5 °C. In NaCl-H₂O system, grain growth occurred gradually in all temperature range.

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The crystal structure of IceXV - the ordered form of iceVI - is reinvestigated. The neutron diffraction pattern of iceXV is carefully analysed and we found that iceXV would be a mixture of several ordered forms. 

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XRD and TEM observations of recovered high-pressure phase Mg₂Cr₂O₅ revealed split spots around the position of h = n + 1/2 (n: integer) in the diffraction patterns of the basic structure of this phase. It was proved that these split spots were formed by the periodic arrangement of the anti-phase boundaries in the structure. Then, the relation between the formation of these periodic anti-phase boundaries and the high-pressure phase transformation of Mg₂Cr₂O₅ is discussed.

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The derivation pyroxenes structures from a common building module and the structure-building operations forming a space groupoid are analyzed in detail.

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We report a model crystal( triclinic crystal shows cubic in diffraction).
We use the homometric triplets of the crclotomic sets ,n=16,
r=7.(Patterson,1944).
The model structure is metrically cubic lattice, space group P1, 343 atoms, and the diffraction symmetry is m3m .  

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Rare–earth elements are often used as activator agents in inorganic phosphors, and high temperature is necessary for synthesis of these phosphors, so there are many problems on the price and energy. Our group reported that large ions can be doped into calcite structure through amorphous calcium carbonate (ACC). In this study, we synthesized calcite phosphors by impurity-doping into ACC followed by pressure-induced crystallization. By introducing strontium into calcite, the lattice volume can be controlled and the crystal field can be changed. We will report change in the photoluminescence spectra of synthesized calcite phosphors with increasing strontium concentration.

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In order to use surface reaction experiments for formation of organics, ice and H₂ molecules on amorphous silicate films, we made experiments of film formation on different substrates using RF sputtering deposition (RFSD), PLD and EBPVD methods. Amorphous silicate films a few tens to a few hundreds nm in depth were formed. Films depleted in Mg were formed by Mg-Si fractionation even in PLD method as well as in RFSD method. Surface morphologies of the films were different on different substrates in RFSD method. It was concluded that RFSD and PLD methods are suitable for large and small substrates, respectively.

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,In this study, we have examined the growth of low-quartz (SiO₂) crystal using X-Li₂O-V₂O₅ flux (X= CaO, MgO, Na₂O, B₂O₃, LiB₄O₇). On examination by growth experiments with several ratios and combinations of flux components, we have succeeded in lowering the crystal growth temperature, where crystals can crystalize in the presence of flux liquid phase, to 550-560ºC, definitely below the low-high phase transition temperature, and in growing hexagonal prismatic crystals with pyramidal faces at each end, which are presumably low-quartz.

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Diffraction study, X-ray emission spectra (XES) experiment, X- ray Moessbauer experiment at HPCAT APS will be presented. Structure transitions of spinels and perovskites are attributed to high-to-low spin transition. The spin state change of is accelerated at higher pressures. The correlation between structural transition and electronic state is investigated by effective charge analysis and electron density deformation by MEM analysis based on the X-ray diffraction intensity at high pressures. Bonding character change inducing structure transformation is elucidated by molecular orbital (MO or DFT) analysis. 

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We have applied ²⁹Si MAS NMR together with first-principles calculation to gain new insights into the cation (Mg, Zn) distribution in (Mg,Zn)₂SiO₄ olivine solid solution, as well as the correlation between ²⁹Si chemical shift and local structures associated with cation distributions. It was demonstrated that ²⁹Si MAS NMR is capable of probing/quantifying the occupancy of cations in the M1 and M2 octahedral sites, and Zn has a preference for M1 sites. This study also revealed that cation substitutions in neighboring edge-shared octahedral sites have greater influence on the ²⁹Si chemical shift as compared to corner-shared sites for olivine. 

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To reveal the distribution of Fe³⁺ between two tetrahedral site in melilite and the relationship between ionic substitution and incommensurate structure, two Fe-Ga-melilite samples were synthesized. The result of Rietveld refinement using X-ray and neutron diffraction data and Mössbauer spectroscopy revealed that Fe³⁺ distribution between T1 and T2 sites but Fe³⁺ prefers T1 sites. Mössbauer spectroscopic method, has a sensitive reaction for behavior of Fe, also indicates Fe³⁺ prefers larger T1 site. Doublets, given by Mössbauer spectroscopy indicate the existence of multiple T1 and T2 sites. This result indicates the incommensurate structure in melilite. Therefore, ionic substitution between T1 and T2 sites give rise to incommensurate structure.

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Fe³⁺-analogue pumpellyite, julgoldite-(Fe³⁺), from Kreimbach-Kaulbach, Germany was studied using EMPA and X-ray single-crystal methods to examine Fe behavior in octahedra and its effect on crystal structure. The relationship between hydrogen bonding system and the oxidation state of transition elements was also considered. Structural formula is represented as ^WCa₂^X(Me^2+/3+)^Y(Me³⁺)₂Si₃O_14-n(OH)_n. The substitution scheme, ^XMe²⁺ + 4OH^- ↔ ^XMe³⁺ + 3OH^- + O^2-, is known to maintain the charge balance. As a result of structural analysis, the site occupancies at X and Y were Fe³⁺_0.40Fe²⁺_0.35Mg_0.16Al_0.08 and Fe³⁺_0.81Al_0.19, respectively. Both <X-O> and <Y-O> increase with increasing with mean ionic radius in each site. 

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Chromium distributions in (CaMgSi₂O₆)₉₅(CaCrAlSiO₆)₅-diopside solid solutions synthesized at 800, 1000 and 1200 ˚C were determined using X-ray Rietveld method to clarify origin of blue color of chromian diopside synthesized at 800 and 1000 ˚C. Site populations of trivalent chromium ions per 6 oxygens at the octahedral and tetrahedral sies are 0.031(3):0.018 at 800 ˚C, 0.047(3):0.004 at 1000 ˚C, and 0.050:0.000 at 1200 ˚C. The results are consistent with those of Ikeda and Yagi (1982).

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The tetragonal hydrogarnet derived from CaGeO₃ tetragonal garnet was synthesized under high pressure and high temperature. The hydrogen positions were determined and the hydrogen bonding was examined by single-crystal X-ray diffraction. Consequently, the bifurcated hydrogen-bond can be formed between an H atom and its adjacent two acceptor O atoms.

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Single-Crystal synchrotron X-ray diffraction study on Al-bearing phase D was conducted to refine its crystal structure.  The axial length of a-axis of our sample is larger than those of the other MgSi-phase D, and that of c-axis is smaller. Moreover, Comparing with Mg-free Al-phase D (Pamato et al., 2015), the trend of axial length with increasing Al content is apparently different. This shows that the Al replacement in phase D structure should affect its structural transformation with its chemical composition change.

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The electronic state change of wadsleyite with Fe²⁺ is investigated by the first-principles calculation technique. The electron orbitals in the Mg₂SiO₄ wadsleyite are distributed only around the oxygen atoms. On the other hand, those in the (Mg_0.5Fe_1.5)SiO₄ wadsleyite are localized at the Fe and O3 atoms, which forms an antibonding orbital between the Fe and O3 atoms. The antibonding orbital would make it impossible to emerge the Fe-wadsleyite phase.

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We investigated a intercorporation of MgCl₂ in Ice VIII using DFT calculations. 

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To enumerate structure ordered of ices easily, hydrogen-bond networks can be represented by adjacency matrixes. Adjacency matrixes give us mathmatical description of ices. Example in ice VI will be presented.

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Hydrogrossulars with different Si-content were
synthesized by hydrothermal synthesis. Si for Al substituted mayenite was
obtained by thermal dehydration of hydrogrossular at 700°C. Si-substituted
mayenite was investigated using powder X-ray diffraction method. The obtained cell
parameters reveal a limit of Si-substitution for Al.

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To determine the structure of boehmite, neutron diffraction pattern experiments
were carried out at BL-11(PLANET) in Materials and Life Science Experimental Facility
of J-PARC. To investigate the compression behavior of boehmite, powder X-ray
diffraction pattern experiments were carried out at BL-18C in Proton Factory.
Rietveld refinements on the neutron diffraction patterns were conducted on the basis of
space group of Cmcm.This space group and the structure model of boehite did not always go together.
To press boehmite at 8.8 GPa, b axis is 5 % shrinkage, a,c axis is 1% shrinkage. Boehmite
have a strong anisotropy.

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Crystal structure of grossular garnet from Jeffrey mine, Canada was examined for a comparison of cation ordering in {211} sector. Result of the refinement with the space group I2/a, cation ordering in {211} sector shows a similar trend of the {211} sector in the andradite garnet from Mali.

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A knowledge of the site occupancies and order-disorder relationships in the amphibole is essential to a better understanding of their crystal chemistry. In this study four natural amphibole were studied by using single-crystal X-ray diffraction method. XRD measurement showed that the T1-O bond lengths are longer than T2-O bond lengths respectively in pargasite and edenite, due to ^[4]Al ordering in T1 site. Also it showed that the M2-O bond lengths are shorter than M1-O and M3-O bond lengths in pargasite, due to ^[6]Ti and ^[6]Al ordering in M2 site.

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Silicon is one of the major and important element that constitutes the Earth’s crust and mantle. An enormous amount of carbon is also contained in the Earth’s interior, which suggests that silicate could be closely interacted with carbon under high-pressure and high-temperature. In this study, we mixed amorphous silica and amorphous carbon and synthesized CO₂-SiO₂ solid solution at high-temperature under ambient pressure. The samples of CO₂-SiO₂ solid solution were carefully examined by powder XRD, EPMA measurement, and so on. We report the effect of the carbon dissolution on a-quartz.

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The effect of cooling rate on the structure of CaSiO₃ glass was investigated by using X-ray diffraction (XRD) measurements, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, and density measurements. Densities of CaSiO₃ glasses decrease with increasing cooling rate. The first sharp diffraction peak (FSDP) position of XRD profiles for ground CaSiO₃ glass shifts from 30.08 to 30.20°with increasing cooling rate. These results may indicate that higher cooling rate is responsible to preserve the 3-membered rings of SiO₄ tetrahedra in the CaSiO₃ glass structure. Because the 3-membered ring is also observed in high temperature form CaSiO₃ crystal (pseudo-wollastonite).

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Protoenstatite(PEN), one of the polymorph of enstatite, is the stable phase at high temperature. It is generally considered that PEN is the unquenchable phase, but some people reported that PEN was observed at room temperature from experimental generative materials. The purpose of this study is to make clear the condition PEN can retain at room temperature which associated with grain size and cooling rate.

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Amorphous calcium carbonate (ACC) is a metastable mineral, and its stability and physical properties depend on water contents in ACC. In this study, structural analysis of ACCs with different water contents was performed using X-ray diffraction method at BL NW10A of PF-AR. Obtained profiles indicated that local structure units of ACC developed with dehydration of ACC.

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The olivine is a main rock-forming mineral of the earth and the meteorite. In the present study, forsterite from Pakistan was used as sample.  For the purpose of an precise determination of the site occupancy of natural olivine with the ALCHEMI experiment,  an experimental study was performed to find a condition that the electron channeling has been produced most effectively. The incidence direction of electron beam was continually changed and the EDS spectrum was acquired. One of the characteristic results is that the intensity of Mn and Ni showed a irregular behavior in the EDS profile.

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Shock-metamorphosed zircons were recovered from the Jack Hills metaconglomerate in the in the Narryer Gneiss Complex, Western Australia. A total of 8993 detrital zircons were investigated for their external and internal structures using a SEM and optical microscope, and four types of shock-metamorphosed zircons were identified; (1) curviplanar features, (2) single or multiple sets of planar features, (3) partly granular features, and (4) fully granular features. Of these four, planar feature is the most diagnostic evidence for impact origin and preserved as annealed  parallel fractures and deformation lamellae.

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Synchrotron powder X-ray diffraction (XRD) and transmission electron microscope (TEM) experiments for annealed sillimanite have been carried out in the present study to examining the P-T conditions which form antiphase boundary (APB) in sillimanite. Our results show that the sillimanite which is expanded (by XRD) shows APB structures by TEM observation. We consider the causes of the volume expansion and APB are the same. The expansion is detected at sillimanite samples annealed above 1100°C. We concluded that APB in sillimanite is the evidence of being heated above 1100°C.

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We report high-temperature and high-pressure in-situ X-ray diffraction study of icosahedral (i)-AlCuFe quasicrystal up to 104 GPa. Result from the high-pressure experiment under ambient temperature shows that there is no obvious change of the diffraction pattern within measured pressure range while two small new peaks are observed above 87 GPa. These results suggest that the i-AlCuFe remain its structure at least up to 75 GPa. On the other hand, the results from the high-temperature and high-pressure experiment show that at high-temperature the i-AlCuFe is readily transformed to crystalline phase and the transformation process is irreversible. 

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The Cretaceous-Tertiary (K-T) boundary clay is also enriched in Cu, Zn, As and Sb.
We have already clarified about the local structure around antimony atoms in
K-T boundary clay by XAFS spectroscopy. In this study, additionally, the Sb
K-edge XANES spectrum of K-T boundary clays is compared with those of various
kinds of reference Sb minerals. There is almost no shift in the threshold
energies between K-T boundary clays and other Sb⁵⁺ oxides. The
oxidation state of Sb is estimated Sb⁵⁺ and Sb seems to form the
Sb-O bond. Sb co-precipitated with As and Fe ions, and then may co-exist in ferric
hydroxides throughout precipitation and diagenesis.

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We examined the microtexture and crystallographic orientation feature of African carbonado to give constraints to their formation mechanism and conditions. Carbonado consists of granular crystals each of which is random in orientation and in contract by irregular zigzag grain boundaries. The unique microtexture is likely not a deformation texture, but a growth texture formed under high driving force in an advective regime in the mantle. Our new finding of inclusions with omphacitic compositions in carbonado suggests its eclogitic origin.

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Pb-bearing aragonite (tarnowitzite) shows a characteristic cathodoluminescence (CL) in a blue region , of which intensity is correlated with Pb content. The spectral peak of a blue emission indicates no shift in its position when a sample temperature changes, suggesting almost no influence of crystal field effect. Pb ions exchanged for Ca ions in tarnowitzite might cause the distortion of its structure, which could derive a defect center related to a blue CL emission.

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