Abstract

A chemical analysis of pavonite from the Ikuno mine, Hyogo Prefecture, Japan, gives Ag 11.14, Cu 0.40, Fe 0.08, Mn 0.01, Pb 0.16, Bi 69.43, S 18.05, for a total 99.27 wt.%, corresponding to (Ag (sub 0.92) Cu (sub 0.06) Fe (sub 0.01) ) (sub Sigma 0.99) (Bi (sub 2.95) Pb (sub 0.01) ) (sub Sigma 2.96) S (sub 5.00) (basis: S = 5). This allows recognition of AgBi 3 S 5 as the ideal formula of pavonite, a composition which now acquires "end-member" status. The X-ray powder pattern is identical to those of Cu-Pb-substituted materials, and was indexed on the monoclinic cell with a 13.34(1), b 4.036(5), c 16.42(1) Aa, beta 94.25(5) degrees . Pavonite occurs as an accessory member in a ferberite-cassiterite-chalcopyrite-quartz-calcite vein accompanied by microscopic scheelite, bismuthinite, native bismuth, pyrite, and a sulfosalt of approximate formula Ag (sub 6.5) Pb 7 Bi (sub 14.5) S 32 , a possible derivative of treasurite. This assemblage is different from those in which pavonite had previously been found. The occurrence is near the center of a system of concentrically distributed veins involving Au-Ag, Pb-Zn, Cu-Zn, Cu, and Sn-W zones; it lies in the Sn-W zone, where neither Ag nor Pb minerals were previously known.

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