1975 Volume 25 Issue 133 Pages 347-357
In this paper, the paragenesis of minerals in the Hoei mine is presented with some remarks on the mineralogical properties of kutnahorite.
The Ichigo (no.1) ore body of the Hoei mine is a massive deposit of Sn, Zn and iron sulfide formed by replacement of the Silurian limestone bed. From this ore body, there have been found various kinds of ore and gangue minerals such as: garnet, clinopyroxene, axinite, tourmaline, vesuvianite, quartz, pyrrhotite, chalcopyrite, arsenopyrite, pyrite, marcasite, sphalerite, galena, native bismuth, herzenbergite, franckeite, jamesonite, cassiterite, stannite, malayaite, fluorite, sericite and carbonate minerals. The species of carbonate minerals are ferromanganoan dolomite, magnesian kutnahorite, kutnahorite, calcian rhodochrosite, ferroan magnesite and manganoan calcite, and they have been crystallized at the later stage of mineralization in this mine.
The kutnahorite in this mine is white, yellow or pinkish in color, and platy or leaf-like in external shape, reaching to 5 cm in maximum length. Its specific gravity ranges from 2.98 to 3.18 by picnometer method. Optically negative, and some examples of refractive indices are ω=1.717-1.731, ε=1.524-1.529. Unit cell constants, a0 = 4.861-4.869 Å, c0=16.24-16.37 Å. The range of chemical composition of kutnahorite is fairly wide, as shown in Table 4 and 5.
Judging from the mode of occurence, microscopic observations and the compositional changes detected by EPMA, the crystallization sequence of the carbonate minerals is suggested as follows : dolomite-ferromanganoan dolomite-magnesian kutnahorite-kutnahorite-calcian rhodochrosite-manganoan calcite.
