Abstract
Zinc sulfate hydroxide hydrate was found as a veinlet in altered shale or stalactiform aggregates in humid gallery at the Hirao mine, Minoo, Osaka, Japan. It occurred as platy hexagonal crystals up to 2 mm across, in association with hydrozincite, smithsonite and namuwite. It was pale blue to colorless with a pearly luster in hand specimen. The mineral has a perfect cleavage. The X-ray powder diffraction data [dA(I)(hkl)] were 10.93(100)(001), 2.723(26)(3-10), 1.576(24)(1-50), 3.642(20)(003), 2.560(16)(-311), 4.16(14)(1-20), 5.47(12)(002), 3.236(12)(-122), 3.409(10)(1-13), 3.285(10)(013), 2.673(10)(121) and so on, and the triclinic cell parameters calculated from the powder data are a=8.36(3), b=8.35(3), c=11.02(1)A, alpha=94.1(3), beta=83.0(2) and gamma=120.0(3)deg. The data agreed with synthetic Zn4(SO4)(OH)6H2O(Bear et al., 1987). The infrared absorption spectrum was measured by the KBr matrix method. The absorption bands around 3400 cm-1 and 1620 cm-1 were attributed to water, and the bands around 1120 cm-1 were attributed to [SO4] tetrahedra. The averaged chemical analysis by EPMA gave ZnO 51.34, CuO 7.25, FeO 0.13, MnO 0.12, NiO 0.12, CoO 0.02, SO3 15.84, H2O 25.18(by difference), total 100 wt%, and the empirical formula calculated on the basis of O=15 is (Zn3.481Cu0.503Fe0.010Mn0.009Ni0.009Co0.001)Sigma4.010(SO4)1.092(OH)5.843.79H2O. The Zn/(Zn+Cu) ratio shows ranging from 0.82 to 0.93.
