On Hydrozincite from Sennodani, Nakatatsu Mine, Fukui Pref., Japan

Abstract

Hydrozincite, as a white powder crusting brown-coloured drusy hemimorphite, has been analyzed., The Sample was obtained from the Nakatatsu Mine, Fukui Prefecture, one of the famous zinc-lead mines in Japan., It consists, under the microscope, of minute fibrous crystals, lining perpendicular to the surface of the crust., The optical properties are : straight extinction, elongation positive, possibly biaxial negative, with α=1., 649, γ=1., 704, Sp., gr., 3., 59 (26°C)., The result of the chemical analysis follows : ZnO 66., 70%, CaO 2., 69, Al2O3 1., 17, Fe2O3 tr., CO2 16., 26 Insol., 0., 26, H2O (+) 11., 75, H2O(-) 1., 55, Total 100., 38., These may be expressed by the formula Zn5(CO3)2(OH)6·H2O., An X-ray powder photograph taken with Cu Kα compares favorably with that of hydrozincite from Deming, New Mexico.,