Hemusite and paraguanajuatite from the Kawazu mine, Shizuoka Prefecture, Japan

抄録

Hemusite from the Ohsawa No. 4 vein, the Kawazu mine, Shizuoka Prefecture, Japan, has a face-centered cubic cell with a=10.800Å. Variable Fe, Sn, Bi and Te contents are given by two representative chemical analyses: Cu 43.80, 42.54; Ag 0.06, 0.24; Fe 0.60, 1.60; Zn 0.08, 0.04; Mn 0.03, 0.03; Cd 0.04, 0.00; Sn 12.09, 8.87; Bi 1.42, 4.18; Te 0.50, 1.21; Mo 10.38, 10.87, S 29.82, 28.96; Se 1.06, 1.09; totals 99.88, 99.63 wt. %. The valency-loaded ideal formula is Cu¹⁺₄Cu²⁺₂Sn⁴⁺Mo⁴⁺S₈ with substitutions of Fe for Cu, (Bi+Te) for Sn, and Se for S. It occurs as very minute blady aggregates composed of seriated grains in a banded hydrothermal quartz vein in close association with tellurian sulphurian paraguanajuatite and chalcopyrite, and less close with sphalerite, djurleite and covellite, the last two being probably of secondary origin. X-ray powder data for paraguanajuatite are indexed on a trigonal cell with a=4.166, c=28.742Å, and the most tellurium-rich analysis gives Bi 63.38, Se 27.53, Te 8.31, S 1.44, total 100.66 wt. %. Relatively higher sulphur activity is expected to favour the formation of hemusite in hydrothermal condition.