<報文>東北地方産ケイ酸マンガン鉱の鉱物学的研究(第19報) : 岩手県田野畑鉱山産セラン石について

概要

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Serandite from the contact metamorphosed bedded manganese ore deposit of Matsumae-oku ore body of the Tanohata Mine occurs as prisms up to 1×2×4 cm in size in albite-microcline-quartz pegmatite dikes cutting the manganese ore deposit. It also includes subordinate amounts of rhodonite, a vanadium-bearing manganoan aegirine, and a zinc-bearing magnesian kozulite. This is the first occurrence of serandite in Japan and also the first case in a silica-saturated assemblage. It is pink to light rose in colour and has perfect cleavages {100} and {001}. The specific gravity is 3.28 (measured on somewhat impure material) ; 3.453 (calculated). In thin section it is colourless and optically biaxial positive with 2V=30° (observed). The refractive indices are α=1.679,β=1.682,γ=1.704. The unit cell constants calculated from the x-ray powder pattern are a_0=7.683A, b_0=6.889A, c_0=6.747A, α=90°32', β=94°07', γ=102°45', Z=2. Chemical analysis leads to an empirical formula (Mn_<1.19>Ca<0.14>Zn<0.03>)_<Σ2.16>(Ma_<0.83>K_<0.02>)_<Σ0.85>H_<0.98>(Si_<2.95>Al<0.02>Fe^<3+>_<0.01>)_<Σ2.98>O_<9.00>, showing the material to be very close to theoretical Mn_2NaH[Si_3O_9].
東北大学の論文
1976-09-30