<報文>東北地方産ケイ酸マンガン鉱の鉱物学的研究(第15報) : 岩手県野田玉川鉱山産含マンガン金雲母について

概要

論文の詳細を見る
Manganoan phlogopite occurs as banded or lenticular aggregate of small scaly crystals ; occassionally a single crystal of tabular of size about 3 mm in hausmannite essential mass at Tsudo-ko of Misago bedded manganese ore deposits of Noda-Tamagawa Mine, in the highly metamorphosed Jurassic quartzite by the intrusion of Tanohata granitic mass. On the basis of 24 (O, OH, F), the chemical analysis yields the formula (K_<1.705>Ca_<0.280>Ba_<0.174>, Na_<0.049>)_<2.208> (Mg_<3.609>Mn_<1.540>Al_<0.484>Fe^<+3>_<0.133>Ti_<0.031>)_<5.797> (Si_<5.361>Al_<2.639>)_<8.000>O_<20.504> (OH_<3.465>F_<0.240>)_<3.465>, which corresponds closely to the general formula for the trioctahedral micas : X_2Y_<6-5>Z_8O_<20>(OH)_4. Structurally, the mineral is of 1M-polytype and monoclinic. The unit-cell parameters are α_0=5.35 ; b_0=9.29 ; c_0=10.29Å ; β=99°52'; and V=503.9Å^3. Megascopically, the color is yellowish-brown with strong pearly luster, and its specific gravity is 2.95. Optically it is negative, with α=1.578 ; β=1.606 ; γ=1.608 ; γ-α=0.030 ; and 2 V≒10°. It is weakly pleochroic with X=co1orless, Y and Z=very pale yellow, where X<Y≒Z. The results of the high-temperature X-ray study and differential thermal analysis indicate that the mineral disintegrates into a mixture of leucite, kalsilite (not exactly determined), olivine (not exactly determined), and galaxite, when heated at about 1,330℃.
東北大学の論文
1974-09-30