Native Copper, Silver, and Gold Accessible to Early Metallurgists

Abstract

The weathered zones of ore deposits, which no longer exist, are reconstructed by inference to provide estimates of relative abundances of usable nuggets of native copper, silver, and gold in ancient times. New analyses and selected data from the literature summarize metallic impurities in native copper, silver, gold, and lead and in the oxidized copper minerals, oxide, silicate, carbonate, chloride, and sulfate, together with impurities in lead carbonate and silver halide minerals. The influence that these occurrences and compositions exerted upon the origin and development of metallurgy in Mesoamerica and South America is discussed in relation to new analyses of artifacts and selected data from the literature. Topics emphasized are: the discovery of smelting and melting by the Moche; the inability of New World metallurgists to smelt copper from sulfide ores or silver from lead ores; and the lack of influence by transoceanic contacts. This paper is contribution number 1702 of the Division of Geological Sciences, C.I.T.