Mineralogy of oxidized ores at the Ik-Davlyat gold-base-metal deposit,the southern Urals

Three types of oxidized ores are identified in the Ik-Davlyat gold-base-metal deposit in the southern Urals: (1) carbonate-sericite-chlorite mineralized rock, (2) vein-shaped quartz-goethite-illite clay, and (3) limonitized rock related to veins. Heavy concentrate of the first type of ore is composed of goethite, rutile, native gold Au_0.91Ag_0.08Cu_0.01, and chalcophanite Zn_1.02Mn_2.98O₄ · 3H₂O. The second type of ore contains goethite, rutile, Pb-bearing jarosite, native gold Au_0.90?0.93Ag_0.06?0.08Cu_0?0.01Fe_0?0.01, silver amalgamide (schachnerite) Ag_0.75Hg_0.97Au_0.98-Ag_0.75Hg_0.97Au_0.28, coronadite (Pb_1.72Mn_7.51Fe_0.41Cu_0.36)₈O₁₆, a chalcophanite-hydrohetaerolite mixture, and cerussite. Gold of the highest fineness (Au_0.98Ag_0.01Cu_0.01) is associated with silver amalgamide. The third type of ore is quite similar to the first variety but contains a jarosite impurity. The composition of oxidized ores indicates a difference in composition of primary ores, in particular, the presence of lead minerals in primary veins. The first finding of chalcophanite in Russia is confirmed by chemical, optical, and X-ray data.