Stannite from the Janggun Mine, Republic of Korea -Contributions to the Knowledge of Ore-Forming Minerals in the Janggun Lead-Zinc-Silver (3)-

한국(韓國) 장군광산(將軍鑛山)의 황석석(黃錫石)에 대(對)하여 -장군(將軍) 연(鉛)·아연(亞鉛)·은(銀) 광석광물(鑛石鑛物)의 지식(知識)에의 기여(寄與) (3)-

In the Janggun mine, stannite occurs as anhedral grains, up to 500 micrometer in long dimension, closely associated with sphalerite, chalcopyrite, arsenopyrite, pyrrhotite, galena and rhodochrosite in the periphery of the South ore body. In reflected light, stannite is grayish yellow green in color and exhibits moderate bireflectance and strong anisotropism without any intenal reflections. Reflection; Rmax. =29.0, Rmin. =27.8 percent at a wavelength of 560nm, and VHN; 219~244kg/mm at a 50g load. The chemical composition on the average from 35 spot analyses by electron microprobe is, Cu 28.0, Fe 12.7, Zn 2.9, Mn 0.2, Sn 25.8, S 30.3, sum 99.9 (all in weight percent); the corresponding chemical formula as calculated on the basis of total atoms=8 is, Cu 1.88 Fe 0.97 Zn 0.19 Mn 0.02 Sn 0.93 S 4.01, which fulfills approximately the ideal formula of $Cu_2FeSnS_4$. The strongest reflections on the X-ray diffraction patterns are; $3.10{\AA}$ (10) (112), $2.72{\AA}$ (5) (020, 004), $1.922{\AA}$ (5) (024), $1.642{\AA}$ (3) (132), $1.244{\AA}$ (3) (143, 136, 235), $1.111{\AA}$(3) (244), $0.958{\AA}$ (1) (048, 422), the patterns are identical with those of literature. From the textural evidence of the microscopic observation, the mineral is considered to have been formed at the middle stage of hydrothermal lead-zinc-silver mineralization.