| Abstract |
Carpholite has been found at the Fukuzumi mine, Hyōgo Prefecture. It forms compact yellow masses or layers in a sheared zone in the silicified footwall of the ore body, associated with quartz and a sm...all amount of calcite. Under the microscope it is fibrous or prismatic. Optically biaxial, 2V_2=67.0°. α=1.624_8, β=1.629_0, γ=1.638_6, γ-α=0.013_8. Pleochroic; X’ golden yellow, Z’ colorless or yellow-tinted, Elongation positive. D_‹meas.› 3.04, D_‹calc.› 3.03. Hardness 5-6. The chemical composition is (Mn_‹0.89›Fe”_‹0.15›)(Fe”’_‹0.07›Al_‹1.91›)(Al_‹0.009›Si_‹1.91›)O_‹5.91›(OH)_‹4.09›. Unit cell dimensions were determined from the X-ray powder data by LIPSON’s method: a=13.83_8, b=20.31_5, c=5.13_0Å. a:b:c=0.681_4:1:0.252_0. The axial ratio is in good agreement with that of ferrocarpholite which is a ferrous iron analogue of carpholite.show more
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17_03_p271