<報文>東北地方産ケイ酸マンガン鉱の鉱物学的研究(第22報) : 岩手県大谷山鉱山産チンゼン斧石について

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The bedded manganese ore deposits of the Ohtaniyama mine occur in the low grade metamorphosed chert of the Permian age. Tinzenite occurs as aggregates of prismatic crystals up to sizes of 5×2 mm in the veins cut through a pyroxmangite concentrate in the braunite ore body at No.3 Koryu drift of the Osono manganese ore deposit. The color is brownish yellow green, luster vitreous, specific gravity 3.36 (meas.) and 3.455 (calc.), and Mohs hardness 6.5. In the thin section, it is colorless and optically biaxial negative with 2V ca. 80°. The refractive indices are a 1.692,β 1.698,γ 1.702 (all±0.003). The unit cell dimensions calculated from the x-ray powder pattern are a 7.16_8,b 9.12_9,c 8.94_7 A, α 91.88°, β 98.88°, γ 76.95°, and V 563.6A^3. Chemical analysis leads to an empirical formula, H_<0.961> (Ca_<1.241>Mn_<1.751>Fe^<2+><0.033>Mg_<0.028>Na_<0.015>K_<0.002>)_<3.070> (Al_<1.845>Fe^<3+>_<0.145>)_<1.990>B_<0.987>Si_<3.991>O_<16.000>, and it is satisfied the definition of tinzenite proposed by Sanero and Gottardi (1968).
東北大学の論文
1978-03-30