Language：English   Publishing type：Research paper (scientific journal)   Publisher：MINERALOGICAL ASSOC CANADA  

Numanoite, the Cu analogue of borcarite, is found in an irregular patch in crystalline limestone near gehlenite-spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Numanoite (up to I mm across) is observed as a core or zones in borcarite crystals up to 5 mm long. The mineral is also found as veinlets up to 0.4 mm wide in aggregates of borcarite crystals. The associated minerals are nifontovite, bultfonteinite, calcite and an unidentified magnesium silicate mineral. In hand specimen, the mineral is blue-green to colorless and transparent with a vitreous luster. The streak is white to pale blue-green. Numanoite is monoclinic, space group C2/m, a 17.794(2), b 8.38 1 (1), c 4.4494(7) angstrom, beta 102.42(2)degrees and Z = 2. The strongest seven lines in the X-ray powder diffraction pattern [d in angstrom(I)(hkl)] are 7.57(100)(110), 2.671(84)(421), 2.727(68)(221), 1.887(52)(041,440), 2.272(48)(331), 2.899(44)(600) and 1.698(34)(640). Electron-microprobe and thermogravimetric analyses gave B2O3 24.09, CaO 38.11, CuO 10.32, MgO 1.02, ZnO 0.51, CO2 15.80, H2O 9.75, sum 99.60 wt.%. The empirical formula, calculated on the basis of 0 = 18, is Ca-3.898(Cu0.744Mg0.145Zn0.036)Sigma 0.925B3.969O5.615(OH)(6.208)(CO3)(2.059), ideally Ca4CuB4O6(OH)(6)(CO3)(2). The mineral is optically biaxial negative, alpha 1.618(2), beta 1.658(2), gamma 1.672(2), and 2V(calc) = 60 degrees. The mineral has perfect cleavages in two directions. The density is 2.96(2) g/cm(3) (meas.) and 2.93 g/cm(3) (calc.). The Vickers microhardness is 376 (290-464) kg/mm(2) (25 g load), and the Mohs hardness number is 41/2. The differential thermal analysis curve shows two endothermic peaks at 489 degrees and 692 degrees C. It is likely that numanoite from the Fuka mine formed by precipitation from late Cu- and Mg-bearing hydrothermal solutions.

DOI： 10.2113/gscanmin.45.2.307

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Publisher：Japan Association of Mineralogical Sciences  

DOI： 10.14824/kobutsu.2005.0.118.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN ASSOC MINERALOGICAL SCIENCES  

Inyoite was found as fissure fillings in calcium borate minerals, which occur as an irregularly shaped body in the crystalline limestone near the gehlenite-spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Inyoite occurs as aggregates of tabular crystals up to 1 mm wide, and rarely as euhedral crystals up to 0.5 mm wide in fissures of calcium borate minerals such as nifontovite, pentahydroborite, sibirskite and parasibirskite. The fissure fillings are composed only of inyoite. This is the first finding of inyoite in Japan. The type of occurrence is also different from those in many other localities in the world. Electron microprobe and CHNS / O analyses gave the empirical formula Ca1.99B5.96O5.92(OH)(10).8.08H(2)O on the basis of O = 24. The unit cell parameters are a = 10.616(2), b = 12.068(1), c = 8.404(1) angstrom and beta = 114.01(1)degrees. The mineral is optically biaxial negative with refractive indices alpha = 1.492, beta = 1.506 and gamma = 1.517, giving a calculated 2V = 82 degrees. The Vickers microhardness is 91 kg mm(-2) (10 g load) and the Mohs hardness number is 2.5. The measured density is 1.875 g cm(-3). It is likely that the inyoite at the Fuka mine was formed by a reaction of ground water with calcium borate minerals at a temperature of around 20 degrees C.

DOI： 10.2465/jmps.99.67

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN ASSOC MINERALOGICAL SCIENCES  

Ramsbeckite was found as a vein forming mineral in altered shale at the Hirao mine, Minoo, Osaka, Japan. It occurred as aggregates of euhedral granular crystals up to 0.5 mm across, in association with sphalerite, chalcopyrite, smithsonite, aurichalcite, amorphous manganese dioxide, schulenbergite, brochantite, serpierite, limonite and an unidentified mineral. It was emerald green to blue-green in color with a vitreous luster in hand specimen. An EPMA and CHNS/O analyzer gave the empirical formula (Cu(9.380)Zn(5.54)2Ni(0.034)Co(0.027)Fe(0.020) Mn-0.013)(Sigma 15.016)[(SO4)(3.871)(CO3)(0.166)](Sigma 4.037)(OH)(21.958)center dot 6.06H(2)O on the basis of O = 44. The unit cell parameters were a = 16.106 (3), b = 15.568 (2), c = 7.109 (1), angstrom, beta = 90.23 (1)degrees, and Z = 2. The mineral was optically biaxial negative with refractive indices alpha = 1.676, beta = 1.704 and gamma = 1.707, and 2V(X)(calc) = 37.8 degrees. The Vickers micro-hardness was 162 (144-182) kg/mm(2) ( 10 g load), and the Mohs hardness was 3.5. The measured density was 3.36 g/cm(3). It is likely that ramsbeckite at the Hirao mine crystallized from Cu and Zn-bearing fluids.

DOI： 10.2465/jmps.99.19

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Dielectric measurements were carried out on suspensions of montmorillonite clay exchanged with three different counterions: sodium, ammonium, and tetramethylammonium (TMA). Only two dielectric absorption peaks could be identified for the clay sample with the TMA counterion, whereas three peaks were found for the two inorganic counterions. The dielectric process observed at around 10 GHz is due to the orientation of bulk water molecules, judging from the relaxation time and relaxation strength. The relaxation strength of the process occurring at around 10 MHz was compared with the coefficient of adiabatic compressibility obtained from ultrasound velocity measurements. The increase in the relaxation strength with decreasing compressibility indicates that the process at around 10 MHz is caused by the orientation of bound water molecules on the clay samples. The relaxation strength of the process occurring at around 10 MHz for the TMA sample was remarkably small. Furthermore, the network structure of the bound water molecules can be characterized by a property peculiar to the TMA sample, taking into account the value of its Cole-Cole parameter. Results for the relaxation strength of the process occurring at around 100 kHz were compared with those for electrophoretic mobility. This comparison revealed that discrimination between bound ions and ions in the diffuse double layer is important, and both the relaxation and electrophoretic results could be satisfactorily explained by surface polarization of the clay. (C) 2003 Elsevier Inc. All rights reserved.

DOI： 10.1016/S0021-9797(03)00688-X

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Phase relationships for FeS polymorph have been studied at the pressure of 16-20 GPa and temperature of 300-1350 K by in situ X-ray observation using a large volume high-pressure apparatus and a synchrotron radiation. Contrary to Fei's prediction [1], we found the stability field of NiAs-type phase of FeS extending at least to 18 GPa. Results of in situ X-ray observation correspond with the NiAs-hexagonal phase boundary determined by Kusaba et al. [2,3], Assuming the straight NiAs-hexagonal phase boundary, we estimate that the NiAs-hexagonal-liquid triple junction is located at 39.5 GPa and 2300 K.

DOI： 10.1080/08957950290006866

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Tohoku University  

Baghdadite was found in a spurrite zone in skarns at Fuka, Okayama Prefecture, Japan. It occurs as anhedral grains up to 0,5 mm in length and prismatic crystals up to 0.6×0.4×0.2 mm, in association with gehlenite, spurrite, tilleyite, peroéskite, grandite garnet and éesuéianite. The empirical formula of the mineral is (Ca3.03Na0.01)∑3.04(Zr 0.83Ti0.15)∑0.98(Si1.99Al 0.01Fe0.01)∑2.01O9 on the basis of O=9, which is consistent with the ideal formula Ca3ZrSi2O9. The unit cell parameters are a= 10.429(2), b= 10.170(2), c=7.365(1)A and β = 91.01(1)°. The mineral is optically biaxial negatiée with refractiée indices a= 1.735, β= 1.747, and γ= 1.755, and calculated 2 V = 1W. The Vickers microhardness is 803 kg mm2 (25 g load) and the density is 3.36 g cm3. It is likely that baghdadite at Fuka was formed by a reaction of pre-existing rankinite and/ or kilchoanite, and ZrO2 eéoléed from an intrusiée igneous liquid at a high temperature.

DOI： 10.2465/jmps.96.43

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Tohoku University  

Kinoite was found in a dump at the Fuka mine, Okayama Prefecture, Japan. It occurs as aggregates of flaky crystals, and rarely as subhedral platy crystals up to 1 mm wide in a vein cutting into crystalline limestone. Associated minerals are stringhamite, calcite and an unidentified mineral. The empirical formula of the mineral is (Ca2.00Mga0.02)∑2.02(Cu 1.92Fe0.04Co0.04)∑2.00Si 2.98O10 · 2.25H2O on the basis of O=10 (anhydrous). The unit cell parameters are a=6.989 (1), b=12.904 (2), c=5.659 (1) Å, and β=96.15 (2)°. The mineral is optically biaxial negative with refractive indices α= 1.642 (2), β= 1.662 (2), and γ= 1.675 (2). The Vickers microhardness is 536 kg mm-2 (50 g load) and the density is 3.14 g cm-3. It is likely that kinoite at the Fuka mine was formed as a primary mineral by a reaction of Cu- and Si-bearing fluids with limestone.

DOI： 10.2465/jmps.96.29

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Tohoku University  

Uralborite, CaB2O2(OH)4, was found in a vein consisting of borate minerals that cut into crystalline limestone at Fuka, Okayama Prefecture, Japan. It occurs as aggregates of fibrous crystals up to 0.2 mm long and as euhedral crystals up to 7 mm long and 3 mm wide, in association with sibirskite, borcarite, fluorite and calcite. Electron microprobe analyses and ICP gave the empirical formula Ca1.006B2.019O2.069(OH)3.931 on the basis of O=6. X-ray powder diffraction were indexed on the monoclinic cell, a=6.923(1), b=12.326(1), c=9.831(1)Å, β=97.09(1)°, determined by a single crystal method. The mineral was optically biaxial positive with refractive indices α=1.605(2), β=1.611(2), γ=1.618(2). The Vickers microhardness was 372 kg mm-2 and the Moh's scale of hardness was 4.5. The density was 2.58(2) g cm-1. It is likely that uralborite at Fuka was formed as a secondary mineral by a late-hydrothermal alteration of sibirskite.

DOI： 10.2465/jmps.95.43

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Language：English   Publisher：Japan Association of Mineralogical Sciences  

Hexahydroborite was found in a vein consisting of borate minerals which developed along the boundary between crystalline limestone and skarns at Fuka, Okayama Prefecture, Japan. Hexahydroborite occurred as aggregates of pyramidal crystals up to 2mm wide on the cavity wall, in association with olshanskyite and calcite. Wet analyses and ICP-MS gave the empirical formula Ca_1.001B_2.102O_4.154·5.846H₂O on the basis of O=10, which was consistent with the ideal formula Ca[B(OH)₄]₂·2H₂O. The reflections of X-ray powder data for hexahydroborite from Fuka were indexed on the monoclinic cell, a=16.011(2), b=6.688(1), c=7.954(2)Å, β=103.81(1)°, determined by single crystal method. The mineral was optically biaxial positive with refractive indices α=1.502(2), β=1.505(2), γ=1.509(2) and had a Mohs hardness of 2.5 and a density of 1.84gcm⁻³. It is likely that hexahydroborite at Fuka was formed by a reaction of ground water with sibirskite and/or parasibirskite at a low temperature around 25°C.

DOI： 10.2465/minerj.21.9

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Language：French   Publishing type：Research paper (scientific journal)   Publisher：Munksgaard Int Publ. Ltd.  

The title compound, a new polymorphic phase of dicobalt diphosphate, Co2P2O7, was prepared by hydrothermal methods. The structure contains CoO6 coordination octahedra and P2O7 groups. The CoO6 octahedra are connected by edge sharing to form six-membered rings, which are further interconnected to form two-dimensional zigzag sheets parallel to (001). The P2O7 groups link these sheets to build three-dimensional networks.

DOI： 10.1107/S0108270197006689

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MUNKSGAARD INT PUBL LTD  

The structure belongs to the monophosphate group and contains one type of PO4 tetrahedra connected to one type of MgO6 octahedra by corner sharing. These PO4-MgO6 groups are connected along the two shorter a and b axes to form two-dimensional zigzag sheets. Two sheets are connected along the longer c axis by two types of Na-O polyhedra. Pairs of PO4 tetrahedra in the sheets are connected by H atoms situated at the centres of symmetry, forming short hydrogen bonds.

DOI： 10.1107/S0108270195006901

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The title structure, Zn2NaH(PO4)2, belongs to the monophosphate group and contains two kinds of PO4 tetrahedra connected by two kinds of ZnO4 distorted tetrahedra. These four kinds of tetrahedra are connected by corner sharing to form sheets parallel to the ac plane. The PO4 tetrahedra are isolated from each other in the sheets. The Na and H atoms are located between the sheets. The Na atoms have six O atoms as nearest neighbours. The H atoms are connected to the apex O atoms of two adjacent sheets by hydrogen bonding.

DOI： 10.1107/S0108270193014337

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Language：English   Publisher：Japan Association of Mineralogical Sciences  

The syntheses of zinc hydroxyl monophosphate Zn₂(OH)PO₄ were carried out under hydrothermal conditions of 573 K and 200 kg/cm². The crystal data are: orthorhombic, P2₁2₁2, a=8.099(1), =8.325(1) and c=5.966(1) Å. The structure was solved by three dimensional Patterson syntheses and refined by least squares methods to give a final residual index of R=0.042. There are four units of Zn₂(OH)PO₄ in a unit cell and three kinds of zinc atoms with different coordinations, where the first zinc atom is six-coordinated by four oxygen atoms and two hydroxyl groups, the second one is octahedrally coordinated by six oxygen atoms and the third one is five-coordinated by four oxygen atoms and one hydroxyl group forming distorted pyramids. The framework consists of infinite straight chains of Zn–O octahedra along c-axis, connected together by isolated PO₄ tetrahedra and distorted Zn–O pyramids. This compound is a polymorph of tarbuttite.

DOI： 10.2465/minerj.17.132

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Authorship：Lead author   Language：French   Publishing type：Research paper (scientific journal)   Publisher：MUNKSGAARD INT PUBL LTD  

The title compound, magnesium sodium phosphate, Mg5Na2(PO4)4, belongs to a group of monophosphates which are constructed from five kinds of coordination polyhedra: two kinds of Po4 tetrahedra are connected by one type of Mg-O octahedra situated at the centres of symmetry; distorted five-coordinated Mg-O polyhedra and another type of distorted Mg-O octahedra are in general positions. Na-O polyhedra occupy the cavities formed by these five types of coordination polyhedra. The density, D(x), of this compound is 3.00 Mg m-3, reflecting the high-pressure synthesis. Similar compounds precipitated at 1 atm. (101.325 kPa) have densities of 2.55-2.82 Mg m-3, corresponding to the lower pressure condition.

DOI： 10.1107/S0108270193012004

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DOI： 10.2465/minerj.16.371

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Other Link： http://ousar.lib.okayama-u.ac.jp/52208

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DOI： 10.18926/ESR/49210

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