Journal of Mineralogical and Petrological Sciences
Online ISSN : 1349-3825
Print ISSN : 1345-6296
Volume 107 , Issue 3
June
Showing 1-5 articles out of 5 articles from the selected issue
ORIGINAL ARTICLES
  • Daisuke NISHIO-HAMANE, Yukikazu OGOSHI, Tetsuo MINAKAWA
    2012 Volume 107 Issue 3 Pages 121-126
    Published: 2012
    Released: July 12, 2012
    [Advance publication] Released: May 30, 2012
    JOURNALS FREE ACCESS
    Miyahisaite, (Sr,Ca)2Ba3(PO4)3F, a new mineral of the hedyphane group in the apatite supergroup, is found in the Shimoharai mine, Oita Prefecture, Japan. Miyahisaite is colorless and occurs as a pseudomorphic aggregate (up to about 100 μm in size) along with fluorapatite in the quartz matrix in a namansilite-rich layer of the chert. Its hardness is 5 on the Mohs scale, and its calculated density is 4.511 g/cm3. The empirical formula of miyahisaite is (Sr1.366Ca0.717)Σ2.083Ba2.911P3.002O12(F0.898OH0.088Cl0.014)Σ1.00, which is representatively shown as (Sr,Ca)2Ba3(PO4)3F. Its simplified ideal formula is written as Sr2Ba3(PO4)3F, which requires 23.25 wt% SrO, 51.62 wt% BaO, 23.89 wt% P2O5, 2.13 wt% F, and -0.90 wt% F = O, for a total of 100.00 wt%. The mineral is hexagonal with a space group P63/m, unit cell parameters a = 9.921 (2) Å, c = 7.469 (3) Å, and V = 636.7 (3) Å3, and Z = 2. The eight strongest lines in the powder XRD pattern [d (Å), (I/I0), hkl] are 3.427 (16) 102, 3.248 (22) 120, 2.981 (100) 121, 2.865 (21) 300, 1.976 (23) 123, 1.874 (16) 140, 1.870 (15) 004, and 1.864 (17) 402. The mineral was formed by the reaction between fluorapatite and the Ba-bearing fluid that produced the aegirine-rich layer with hydrous Ba-rich minerals during the late-stage activity.
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  • Hiroki OKUDERA, Akira YOSHIASA, Kei-ichiro MURAI, Maki OKUBE, Takashi ...
    2012 Volume 107 Issue 3 Pages 127-132
    Published: 2012
    Released: July 12, 2012
    JOURNALS FREE ACCESS
    Local structures around Fe and chemical shifts in X-ray absorption fine structure (XAFS) spectra were investigated for synthetic Fe1-dO, Fe3O4 (magnetite), γ-Fe2O3(maghemite), and SrFeO3-e, as well as natural Fe3O4 and α-Fe2O3 (hematite) specimens. XAFS spectra near the Fe K-edge were measured at BL-9C and BL-12C of the Photon Factory, KEK, Japan. Similar measurements for Fe-N pairs in Fe nitrides (FeN, Fe2N, Fe4N) were obtained for comparison. The X-ray absorption near edge structure (XANES) spectra for various iron compounds, in particular Fe3O4 and γ-Fe2O3, and FexN specimens, showed clear chemical shifts of half-maximum positions with the changing oxidation states of the Fe ions in their structures. The energy at half maximum position should be used for the quantitative discussion of the oxidation and valence states of the Fe ion in Fe compounds rather than the threshold energy E0 found using differentiating XAFS spectra. The δ values in Fe3-δO4 (δ=0.333 for end-member γ-Fe2O3) for magnetite and maghemite were estimated by the extent of the chemical shifts. Decreases in the average Fe-O distances and extended X-ray absorption fine structure (EXAFS) Debye-Waller factor σ2 values for spinel-type Fe3-δO4 solid-solutions were consistent with the estimated δ values. The error in proving the Fe3+/Fetotal ratio in the system by the XAFS method would appear to be less than ±0.10, and higher reliability than this value would be acquired in the comparison of relative values at half-maximum positions.
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  • Juraj MAJZLAN, Biljana LAZIC, Thomas ARMBRUSTER, Michel B. JOHNSON, Ma ...
    2012 Volume 107 Issue 3 Pages 133-148
    Published: 2012
    Released: July 12, 2012
    JOURNALS FREE ACCESS
    Bukovskýite is a relatively rare secondary ferric arsenate-sulfate. At the type locality near the municipality of Kutná Hora (Czech Republic), it is the main secondary mineral in the medieval dumps, where it occurs in enormous amounts and forms nodules of prodigious dimensions. We investigated the mineral bukovskýite and the type locality in detail to understand the abundance of the mineral at this locality. The crystal structure of bukovskýite was solved for bukovskýite crystals from Großvoigtsberg (Germany) and found to be of the space group P1 with a final R factor of 5.08% from 2403 reflections. The lattice parameters at room temperature are a = 7.549(1) Å, b = 10.305(1) Å, c = 10.914(2) Å, α = 115.136(3)°, β = 99.798(3)°, and γ = 92.864(3)°. The structure consists of octahedral-tetrahedral Fe-arsenate chains. Sulfate tetrahedra are bonded to the chains and free H2O molecules via a complicated network of hydrogen bonds. Calorimetric measurements (acid-solution calorimetry atT = 298.15 K and relaxation calorimetry yielded heat capacities from T = 0.4 K to 300 K) gave an enthalpy of formation of -4742.4 ± 3.8 kJ·mol-1 and standard entropy of 615.2 ± 6.9 J·mol-1·K-1. A combination of these values gives a Gibbs free energy of formation of -3968.9 ± 4.3 kJ·mol-1 and aqueous solubility product (log K) of -30.627. Bukovskýite is metastable with respect to scorodite; if scorodite is not considered in the thermodynamic calculations, a stability field of bukovskýite appears at low pH and high sulfate and arsenate activity. Field observations showed that bukovskýite occurs in dumps where the space between the rock fragments is filled by clays. Bukovskýite crystallizes from Fe-As-S-rich gels that replace Si-Al gels. The exact mechanisms that control the entire process are not clear but will be the subject of further studies. We presume that the clays play an important role in creating microenvironments where the activity of the components needed for bukovskýite crystallization remains high for a long time. Bukovskýite is then an intermediate step in the conversion of the unstable gels to the stable assemblage of scorodite and iron sulfates.
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  • Toshiro NAGASE, Hidemichi HORI, Mizuya KITAMINE, Mariko NAGASHIMA, Ahm ...
    2012 Volume 107 Issue 3 Pages 149-154
    Published: 2012
    Released: July 12, 2012
    JOURNALS FREE ACCESS
    Tanohataite, LiMn2Si3O8(OH), the Li analogue of serandite, has been found in a metamorphosed manganese ore deposit of the Tanohata mine, Iwate Prefecture, Japan. The mineral has the triclinic space group P1 with a = 7.612(7), b = 7.038(4), c = 6.700(4) Å, α = 90.23(6)°, β = 94.70(7)°, γ = 105.26 (8)°, V =345.0(3) Å3, and Z = 2. The seven strongest lines in the X-ray powder diffraction pattern are [d(Å), (I), (hkl)]: 6.64(35)(001), 3.67(26)(200), 3.13(89)(102), 3.11(69)(211), 2.95(100)(102), 2.81(33)(120), and 2.18(40)(103). Electron microprobe analysis and laser ablation microprobe-inductively coupled plasma-mass spectrometry gave an SiO2 content of 51.97; MnO, 37.99; MgO, 1.06; CaO, 0.41; Na2O, 1.97; Li2O, 3.34; total, 96.74 wt%, corresponding to an empirical formula of (Li0.78Na0.22)Σ1.00(Mn1.86Ca0.03Mg0.09)Σ1.98Si3.01O8(OH) on the basis of O = 9. Tanohataite is transparent and pinkish white with a vitreous and silky luster. The streak is white. The cleavage is perfect on {001} and {100}. On the Mohs' scale, the hardness is 5-51/2. The calculated density is 3.33 g/cm3. Optically, tanohataite is biaxial positive with 2Vcalc = 82(2)°, α = 1.593(3), β = 1.618(3), and γ = 1.653(3). Tanohataite occurs as an aggregation of fibrous crystals in veinlets composed mainly of quartz, aegirine, Mn-arfvedsonite, nambulite, natronambulite, and barite.
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Errata
  • 2012 Volume 107 Issue 3 Pages 155
    Published: 2012
    Released: July 12, 2012
    JOURNALS FREE ACCESS
    The following are errata for the original article entitled “Epidote-Sr, CaSrAl2Fe3+(Si2O7)(SiO4)(OH), a new mineral from the Ananai mine, Kochi Prefecture, Japan” by Tetsuo MINAKAWA, Hiroyuki FUKUSHIMA, Daisuke NISHIO-HAMANE and Hiroyuki MIURA (Vol. 103, no. 6, 400-406, 2008). O is missing before (OH) by the authors' mistake.

    Title: CaSrAl2Fe3+(Si2O7)(SiO4)(OH) should be changed to CaSrAl2Fe3+(Si2O7)(SiO4)O(OH).
    Abstract, line 1: CaSrAl2Fe3+(Si2O7)(SiO4)(OH) should be changed to CaSrAl2Fe3+(Si2O7)(SiO4)O(OH).
    INTRODUCTION, line 2: A2M3 (T2O7)(TO4)(OH) should be changed to A2M3(T2O7)(TO4)O(OH).
    INTRODUCTION, line 9: Ca2Al2Fe3+(Si2O7)(SiO4)(OH) should be changed to Ca2Al2Fe3+(Si2O7)(SiO4)O(OH).
    INTRODUCTION, line 29: CaSrAl2Fe3+(Si2O7)(SiO4)(OH) should be changed to CaSrAl2Fe3+(Si2O7)(SiO4)O(OH).
    CHEMICAL PROPERTIES, line 26-27: CaSrAl2Fe3+(Si2O7)(SiO4)(OH) should be changed to CaSrAl2Fe3+(Si2O7)(SiO4)O(OH).


    The pattern of Serpentinite of Figure 1 on page 100 entitled “Finding of prehnite-pumpellyite facies metabasites from the Kurosegawa belt in Yatsushiro area, Kyushu, Japan” by Kenichiro KAMIMURA, Takao HIRAJIMA and Yoshiyuki FUJIMOTO (vol. 107, no. 2, 99-104, 2012) is missing. Below is the corrected Figure 1. The Printer apologizes for the misprint.
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