The mineralogy of a silver-rich area in the Edwards zinc-lead mine, New York

The ore of the zinc-lead deposits of the Balmat-Edwards district in northern New York is mainly composed of very coarse-grained sphalerite, galena and pyrite. Galena concentrates (60% lead) contain an average of 514 g/t of silver, presumably in solid solution. An unusual silver-rich zinc-lead ore pocket at the Edwards mine contains nearly 1% silver. Fine-grained sphalerite, native silver, argentite, freibergite and arsenopyrite occur in association with chalcopyrite and pyrite as fracture-fillings in calcite. Electron-microprobe analyses indicate that freibergite contains = or <25.8% Ag, with an average composition of Cu (sub 1.87) Ag (sub 1.26) Sb (sub 0.98) As (sub 0.22) S (sub 3.25) .