著者

Daisuke NISHIO–HAMANE Koichi MOMMA Masayuki OHNISHI Sachio INABA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.117, no.1, pp.220728, 2022 (Released:2022-11-29)

参考文献数

24

被引用文献数

1

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Oxyyttrobetafite–(Y) is the first member in the betafite group of the pyrochlore supergroup found in albite–rich pegmatite from Souri Valley, Komono, Mie Prefecture, Japan. This new mineral occurs as small anhedral grains with sizes of 20 to 200 µm in cylinder–shaped aggregates with a substrate of thalénite–(Y) and synchysite–(Y). Small amounts of aeschynite–(Y), thorianite, and thorite are also associated in the same occurrence with oxyyttrobetafite–(Y), and gadolinite–(Y) is also included at the boundary between the aggregate and albite. The physical properties are: brown in color, brittle, transparent, non–fluorescent, vitreous luster, white streak with a Mohs hardness of 5, and a calculated density of 5.54 g·cm−3. Oxyyttrobetafite–(Y) is an optically isometric material with brown color under the microscope with a refractive index of n = 2.3 calculated using the Gladstone–Dale relationship. The empirical formula of oxyyttrobetafite–(Y) calculated on the basis of B = 2 with A2B2X6Y composition is (Y1.58Dy0.13Yb0.07Er0.06Tm0.05Gd0.04Ho0.03Sm0.02Tb0.02Eu0.01Lu0.01)Σ2.02(Ti1.85Ta0.09Fe0.05Sn0.02Nb<0.01)Σ2O7.05 and leads to the ideal formula of Y2Ti2O6O, which requires TiO2 41.44 wt% and Y2O3 58.56 wt%, total 100 wt%. The structure is isometric cubic with the space group Fd3m and unit cell parameters of a = 10.11090(10) Å, V = 1033.64(3) Å3, and Z = 8 by single crystal X–ray diffraction measurements. The seven strongest peaks in the powder X–ray diffraction pattern [d in Å (I/I0) hkl ] were 2.918(100) 222, 2.527(18) 400, 2.321(13) 331, 1.788(53) 440, 1.525(46) 622, 1.162(13) 662, and 1.033(9) 844 with unit cell parameters of a = 10.121(3) Å, V = 1036.6(9) Å3, and Z = 8. The crystal structure was refined to R1 = 0.018 for 159 observed reflections with the criteria of I > 2σ (I ). Oxyyttrobetafite–(Y) is characterized by Y dominance at the A sites, Ti dominance at the B sites, and O dominance at the X and Y sites in the A2B2X6Y pyrochlore–type formula.

著者

Yasuyuki BANNO Koichi MOMMA Ritsuro MIYAWAKI Michiaki BUNNO

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.220724, (Released:2023-02-04)

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Katoite, ideally denoted as {Ca3}[Al2](□xSi3-x)(OH)4xO12-4x, where 1.5 < x ≤ 3, was found in skarn xenoliths from Tadano, Fukushima Prefecture, Japan, and investigated by electron microprobe analyses, X-ray single crystal structure refinement, and infrared (IR) spectroscopy. Katoite characteristically contains up to 0.18 atoms per formula unit (apfu) of S and has a range of compositions, wherein Si = 0.96-1.25 apfu, Al = 1.47-1.74 apfu, Fe = 0.13-0.28 apfu, and Mg = 0.01-0.10 apfu. A difference Fourier map revealed the residual electron density near the octahedral Y site (Wyckoff position = 16a), and we interpreted that S with three-fold coordination occurs at the position of the residual electron density, which is represented as the Y’ site (Wyckoff position = 32e). The final refinement introduced the Y’ site to yield R1 [F2 > 2σ(F2)] = 0.0353 with space group Ia3d and unit cell parameter a = 12.24095(8) Å. The IR spectrum in the range of 800-1200 cm-1 shows a band at 1124 cm-1 due to ν3(SO4) and doublet bands at 879 and 931 cm-1 with different absorbances interpreted as ν3(SiO4) overlapping with ν3(SO3). The combined results of IR spectroscopy and structure refinement imply that in the Tadano katoite, S4+ and S6+, forming (SO3)2- and (SO4)2- coordinations, are placed at the Y’ and tetrahedral Z sites, respectively. Assuming that S is preferentially allotted to the Y’ site as S4+ to compensate for the deficiency of the octahedral cations Al, Fe, Mg, Mn, and Ti at the Y site, chemical formulae, including possible S4+ and S6+ contents, may be calculated. The average chemical formula for 14 different spots is as follows: {Ca3}[(Al1.614Fe3+0.208Mg0.063Ti0.019)Σ1.90S4+0.096]Σ2.00(□1.867Si1.120S6+0.013)Σ3.00[(OH)7.192O4.612F0.147Cl0.048]Σ12.00.

著者

Hidetomo HONGU Akira YOSHIASA Ginga KITAHARA Yumiko MIYANO Karin HAN Koichi MOMMA Ritsuro MIYAWAKI Makoto TOKUDA Kazumasa SUGIYAMA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.200904, (Released:2021-09-30)

被引用文献数

2

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Parasymplesite and vivianite specimens were obtained from Kiura Mine, Ohita, Japan and Tomigaoka, Nara, Japan, respectively. Empirical chemical formulas of the specimens determined by energy–dispersive X–ray spectroscopy on the scanning electron microscopy were Fe3(AsO4)2·8H2O, and (Fe0.93Mn0.06Mg0.01)3(PO4)2·8H2O, respectively. The crystal structures of parasymplesite and vivianite determined by single–crystal X–ray diffraction method were monoclinic, space group C2/m, with unit–cell parameters: a = 10.3519(10), b = 13.6009(13), c = 4.7998(4) Å, β = 104.816(2)°, V = 653.32(11) Å3 (Z = 4), and monoclinic, space group C2/m, with unit–cell parameters: a = 10.1518(6), b = 13.4327(7), c = 4.7005(3) Å, β = 104.692(2)°, V = 620.03(6) Å3 (Z = 4), respectively. The crystal structure of parasymplesite solved with the ideal chemical formula was refined to the R1 value of 0.0301 (wR2 = 0.0788) for 722 independent reflections with |Fo| > 4σ(|Fo|), whereas that of vivianite was refined to the R1 value of 0.0272 (wR2 = 0.0832) for 664 independent reflections. The hydrogen atom positions determined by the difference Fourier method coincided with the positions where residual electron density peaks appeared. In the edge–sharing Fe2O6(H2O)4 double octahedra in parasymplesite and vivianite, the bond distance of Fe2–O5, where O5 is the oxygen atom of the H2O molecule, is shorter than that of Fe2–O2. In each arsenate and phosphate phase, only the M2–O2 bond distance shows an increase trend with the increase in the average ionic radii of the M2 site, but the M2–O3 bond distance never shows a clear average M2 ionic radius dependence. In vivianite group minerals, a distortion at the isolated M1O2(H2O)4 octahedra increases as a function of the average M1 ionic radius. The respective complex sheets consisting of the TO4 tetrahedra, isolated M1 octahedra, and edge–sharing M2 double octahedra are connected only by the hydrogen bond O5–H52•••O4. In the arsenate phases, the donor–acceptor distance between O5 and O4 exhibits an increase trend as increase of the average M ionic radius, but in the phosphate phases, there is no clear correlation between donor–acceptor distances and the average M ionic radius.

著者

Yasuyuki BANNO Koichi MOMMA Ritsuro MIYAWAKI Shigeo YAMADA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.114, no.1, pp.33-40, 2019 (Released:2019-03-08)

参考文献数

20

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Chemically heterogeneous amphibole, ranging in composition from magnesio–riebeckite through ferri–ghoseite to clino–suenoite, was found in a specimen of Sanbagawa quartz schist from the Iimori region of the western Kii Peninsula, central Japan. The amphibole exhibits a continuous solid solution between BNa and BMn2+ (BMn2+ = 0–1.82 atoms per formula unit). Most of the amphibole crystals comprise a Mn–poor core and a Mn–rich rim, and ferri–ghoseite often occurs near the boundary between core and rim. The crystal structure of a single crystal fragment of ferri–ghoseite, which has an averaged composition of A(Na0.16K0.02)Σ0.18B(Na0.83Ca0.09Mn2+1.08)Σ2.00C(Mg3.78Mn2+0.52Fe3+0.66Al0.04)Σ5.00T(Si7.95Al0.05)Σ8.00O22W[(OH)1.90F0.10]Σ2.00 based on electron–microprobe analyses, was refined to a R1 of 6.7%, has unit cell parameters of a = 9.6389(7), b = 18.0534(10), c = 5.3138(3) Å, and β = 102.896(2)°, and is in space group C2/m with Z = 2. The site populations for B cations of the ferri–ghoseite are M4(Na0.83Ca0.09)M4’Mn2+1.08, which also confirms the B(Na,Mn2+) solid solution. Sector–zoned aegirine occurs in the amphibole–bearing quartz schist from Iimori, and it is assumed that most of the metamorphic minerals in the quartz schist formed under non–equilibrium conditions. Therefore, taking into account the miscibility gap between sodium amphibole and clino–suenoite, the solid solution between BNa and BMn2+ in the amphibole can be inferred to have resulted from rapid, non–equilibrium crystallization rather than high–T equilibrium crystallization.

著者

Daisuke NISHIO–HAMANE Masayuki OHNISHI Norimasa SHIMOBAYASHI Koichi MOMMA Ritsuro MIYAWAKI Sachio INABA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.115, no.3, pp.286-295, 2020 (Released:2020-06-24)

参考文献数

30

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Petersite–(La) is a new mineral of the petersite series in the mixite group with an ideal formula of Cu6La(PO4)3(OH)6·3H2O from Ohgurusu, Kiwa–cho, Kumano City, Mie Prefecture, Japan. The mixite–group minerals occur in small cavities coated by chrysocolla developed along quartz veins. Four members from different cavities have been identified: petersite–(La), petersite–(Ce), petersite–(Y), and agardite–(La). Petersite–(La) occurs as a radial aggregate formed by acicular to hexagonal columnar crystals of yellowish green color. Crystals are elongated along [001] and the prismatic face is probably formed by {001} and {100} or {110}. It is non–fluorescent in UV light. Crystals are brittle, cleavage and parting are non–observed, and fracture is uneven. These characteristics are common in other mixite–group minerals. The calculated density of petersite–(La) is 3.33 g/cm3, based on the empirical formula and powder XRD data. It is optically uniaxial positive with ω = 1.680(3) and ε = 1.767(3) (white light), and pleochroism varies from light green to yellowish green. Based on the WDS analysis, the empirical formula of petersite–(La) calculated on the basis of P + As + Si = 3 is (Cu5.692Fe0.010)Σ5.702[(La0.148Ce0.122Nd0.117Y0.086Sm0.022)Σ0.495Ca0.372]Σ0.866(P1.890As0.799Si0.311)Σ3O10.320(OH)7.680·3H2O. Petersite–(La) is hexagonal (P63/m) with a = 13.367(2) Å, c = 5.872(2) Å, and V = 908.7(4) Å3 (Z = 2). The eight strongest lines of petersite–(La) in the powder XRD pattern [d in Å(I/I0)(hkl )] are 11.578(100)(100), 4.377(28)(210 + 120), 3.509(18)(211 + 121), 3.211(10)(310 + 130), 2.898(14)(221, 400), 2.656(10)(320 + 230), 2.526(11)(410 + 140), and 2.438(25)(212 + 122). Petersite–(La) is the third defined member in the petersite series and corresponds to the La–dominant analogue of petersite–(Y) and petersite–(Ce).

著者

Toshiro NAGASE Koichi MOMMA Takahiro KURIBAYASHI Masahiko TANAKA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.108, no.2, pp.87-93, 2013 (Released:2013-05-03)

参考文献数

21

被引用文献数

2

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Lutecite is an aggregate of microcrystalline silica; its variety with a hexagon form is known as hexalite. Textures of lutecite and hexalite from the Arz-Bord Range, in northwestern Gobi, Mongolia, and from Banyan-obo, China, were observed by optical microscopy, synchrotron X-ray diffraction, and transmission electron microscopy (TEM). Cross sections of lutecite and hexalite observed through optical microscopy show fibrous textures. TEM observations revealed that the quartz crystals constituting each fiber exhibit irregular shapes elongated parallel to [212], which is nearly perpendicular to (101); a width of 0.5 μm; and length of a few micrometers. The results of selected area electron diffraction analyses show that the fiber bundles have V-shaped cross textures, and the crystals are twinned according to the Reichenstein-Grieserntal law. X-ray diffraction analysis indicates a total moganite content of approximately 10 wt% in this lutecite aggregate, and moganite appears as irregular-shaped domains within quartz under high-resolution TEM.