東北地方産ケイ酸マンガン鉱の鉱物学的研究(第2報) : 岩手県三根鉱山産スペサルチンについて

概要

論文の詳細を見る
Spessartine crystals with the maximum diameter of about 1.5cm and with the faces of (211) and (110) rarely occur in tourmaline-orthoclase-quartz bearing pegmatites cutting through the bedded manganese silicate ore deposits of Mitsune mine of older Cretaceous age. The colour is pale brownish-yellow and in a thin section pale pink, and the outer zone of the crystal exhibits definite zoning. The specific gravity is 4.032,Vickers microhardness (load 100g) 1,080,refractive index 1.801 (average) and unit cell edge a=11.648A. The chemical analysis gives the formula : [chemical formula] and the molecular percentages of end-members are spessartine 67.11,almandine 15.40,grossular 9.04,andradite 5.62 and pyrope 2.83. The high-temperature X-ray study and the differential thermal analysis indicate that the mineral breaks down to a mixture of anorthite, magnetite and jacobsite when heated to about 1,190℃.
東北大学の論文
1967-11-05