- 著者
- Daisuke NISHIO-HAMANE Masayuki OHNISHI Tetsuo MINAKAWA Jun-ichi YAMAURA Shohei SAITO Ryo KADOTA
- 出版者
- 一般社団法人日本鉱物科学会
- 雑誌
- Journal of Mineralogical and Petrological Sciences (ISSN:13456296)
- 巻号頁・発行日
- vol.107, no.1, pp.1-7, 2012 (Released:2012-02-29)
- 参考文献数
- 17
- 被引用文献数
- 3 7
The first Cr-dominant amphibole, ehimeite, ideally NaCa2Mg4CrSi6Al2O22(OH)2, has been found in a chromitite deposit in the Akaishi Mine, Higashi-Akaishi Mountain, Ehime Prefecture, Japan. Ehimeite occurs as prismatic crystals of up to 1.5 cm in length and 0.5 cm in width and is found in association with chromite, kämmererite (Cr-rich clinochlore), Cr-poor clinochlore, phlogopite, and uvarovite. It is transparent, emerald green to pale green in color with pale green streaks, and has a vitreous luster. Optically, it is biaxial positive with α = 1.644(2), β = 1.647(2), γ = 1.659(2), and 2Vcalc. = 53°. It has a Mohs’ hardness of 6 and densities of 3.08(3) g/cm3 (measured using heavy liquids) and 3.121 g/cm3 (calculated from powder diffraction data and the empirical formula). The empirical formula is (Na0.88K0.07)Σ0.95(Ca1.89Na0.02Mg0.09)Σ2.00(Mg4.03Cr0.62Al0.19Fe3+0.07Fe2+0.07Ti0.03)Σ5.00(Si6.14Al1.86)Σ8.00O22(OH)2 on the basis of O = 22 and OH = 2, and ehimeite mainly forms a solid solution, NaCa2Mg4(Cr, Al)Si6Al2O22(OH)2, with pargasite. It has a monoclinic unit cell with a = 9.9176(14) Å, b = 18.0009(12) Å, c = 5.2850(7) Å, β = 105.400(7)°, V = 909.6 (17) Å3, and Z = 2, and it belongs to the space group C2/m, as refined from powder XRD data. The eight strongest lines in the powder XRD pattern [d (Å), I/I0, hkl] are (3.370, 58, 150), (2.932, 43, 221), (2.697, 81, 151), (2.585, 50, 061), (2.546, 100, 202), (2.346, 42, 351), (2.156, 35, 261), and (1.514, 55, 263). The crystal structure has been refined to R1 = 0.0488 using single-crystal XRD data. It has been concluded that ehimeite in the Akaishi Mine was formed by the reaction of chromitite and the metamorphic fluid in the retrograde stage of serpentinization during the Sanbagawa metamorphism.
- 著者
- Daisuke NISHIO-HAMANE Yukikazu OGOSHI Tetsuo MINAKAWA
- 出版者
- 一般社団法人日本鉱物科学会
- 雑誌
- Journal of Mineralogical and Petrological Sciences (ISSN:13456296)
- 巻号頁・発行日
- vol.107, no.3, pp.121-126, 2012 (Released:2012-07-12)
- 参考文献数
- 12
- 被引用文献数
- 3 2
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.
- 著者
- Daisuke NISHIO-HAMANE Tetsuo MINAKAWA Hanako OKADA
- 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.109, no.1, pp.34-37, 2014 (Released:2014-02-22)
- 参考文献数
- 10
- 被引用文献数
- 2 6
Iwateite, Na2BaMn(PO4)2 is a new mineral, which was found in the manganese ore of the No. 3 (Matsumaezawa) deposit in the Tanohata mine, Tanohata Village, Iwate Prefecture, Japan. Iwateite has a glaserite structure, which occurs as granular to anhedral inclusions of 10-100 μm in the main constituent minerals in manganese ore and sérandite crystal. It is colorless with white streaks, non-fluorescent, and it displays very weak pleochroism. Iwateite crystallizes in the trigonal system and belongs to the P3 space group where, a = 5.3642(10), c = 7.039(2) Å, V = 175.41(8) Å3, and Z = 1, with a calculated density of 4.06 g/cm3.