岩手県宮守地方の単斜輝石角閃石岩中の普通角閃石

抄録

The mineral common hornblende was separated from clinopyroxene-hornblendite in the ultramafic mass of the Miyamori district, northeastern Japan. The common hornblende, which crystallized after the formation of associating clinopyroxene (Wo₄₄En₂₇Fs₂₉ in molecular %) in magmatic condition, shows the following optical, physical and chemical characters:
α=1.652 X: pale yellow
β=1.669 γ-α=0.027 Y: dark brown
γ=1.679 Z: dark brown
(-)2V=78°(calculated), =80°_??_81.5°(observed)
c∧Z=20.1°
D=3.17
(Ca_1.978 Na_0.438 K_0.019)_2.435 (Al_0.387 Fe'''_0.392 Fe''_1.565 Mg_2.548 Mn_0.083)_5.087 (Si_{6. ?? 31} Al_1.669)_8.000 O_21.909 (OH)_2.091
The X-ray powder diffraction data of the mineral is given in Table 3.