Potassicleakeite, a New Amphibole from the Tanohata Mine, Iwate Prefecture, Japan.
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Accession number;02A0930838
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| Title;Potassicleakeite, a New Amphibole from the Tanohata Mine, Iwate Prefecture, Japan. |
| Author;
MATSUBARA S
(National Sci. Museum, Tokyo, Jpn)
MIYAWAKI R
(National Sci. Museum, Tokyo, Jpn)
KUROSAWA M
(Univ. Tsukuba, Ibaraki, Jpn)
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Journal Title;J Mineral Petrol Sci
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Journal Code:G0150B
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ISSN:1345-6296
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VOL.97;NO.4;PAGE.177-184(2002)
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| Figure&Table&Reference;FIG.1, TBL.7, REF.23 |
| Pub. Country;Japan |
| Language;English |
| Abstract;Potassicleakeite, KNa2Mg2Fe3+2LiSi8O22(OH)2, the K-dominant leakeite, is found in manganese ore deposit at the Tanohata mine, Iwate Prefecture, Japan. It is monoclinic, C2/m, a=9.922(5), b=17.987(7), c=5.286(2) .ANGS., .BETA.=104.07(3).DEG., V=915.1(7) .ANGS.3 and Z=2. The seven strongest lines in the X-ray powder diffraction pattern are 8.48(67)(110), 4.50(89)(040), 3.40(46)(131), 3.28(45)(240), 3.16(72)(310,201), 2.83(49)(330), 2,53(100)(202). Electron microprobe and LAM-ICP-MS analyses gave SiO2 55.34, TiO2 0.29, Al2O3 0.44, V2O3 5.52, Fe2O3 9.45, MnO 7.81, MgO 7.23, CaO 0.13, K2O 3.10, Na2O 8.73, Li2O 1.2, H2O (calc) 2.08, total 100.12wt.%, corresponding to (K0.57Na0.46).SIGMA.1.03(Na1.98Ca0.02).SIGMA.2.00(Mg1.29Mn0.65).SIGMA.1.94(Fe3+1.02V0.64Mg0.26Al0.05Ti0.03).SIGMA.2.00(Li0.70Mn0.30).SIGMA.1.00(Si7.98Al0.02).SIGMA.8.00O22(OH)2 on the basis of O+OH=24. It is transparent and reddish brown with vitreous luster. The streak is pale brownish yellow and cleavage {110} is perfect. The fracture is uneven and tenacity is brittle. The hardness is VHN100 425-572kg/mm2 (Mohs -5). The calculated density is 3.18g/cm3. It is distinctly pleochroic from yellowish brown to reddish brown. It is optically biaxial positive with .ALPHA.=1.672(2), .BETA.=1.680(2), .GAMMA.=1.692(2), 2V(calc)=79.DEG., and orientation: b=Z, X.AND.c=+35 to 40.DEG.. It occurs as prismatic crystals in veinlets composed mainly of quartz, alkali-feldspars, and serandite. The mineral is considered to be formed under the later stage of hydrothermal activities of contact metasomatism. (author abst.) |
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