A study of ancient copper

Conclusions

• 1. The ingot from the Mourner mine (Central Balkans) is represented by bronze, i.e., a natural alloy whose composition includes (in the order of decreasing content) iron, zinc, arsenic, sulfur, nickel, silver, and antimony. Its natural appearance in the smelting process is explainable by the fact of the existence of a polymetal ore in the mine.

• 2. The ingot from Kargaly (Southern Urals) is represented by ideally pure copper with globular inclusions of Cu₂S sulfides located along grain boundaries and in the bulk of the grains. This gives us grounds to assume that the oxidized ore from which the Kargaly copper was melted contained sulfur-bearing components. The same inference follows from the results of the study of a pricker made of the Kargaly copper.

• 3. Analyzing the microstructure and hardness of the Kargaly copper in studying the pricker we established that cast copper was subjected to cold plastic deformation and shortterm recrystallization annealing in the second millennium B.C.

• 4. We detected a sulfur admixture in copper specimens melted from ores fundamentally different in their mineralogical and geochemical characteristics. This means that quite substantial corrections should be made in the existing concept that this impurity can appear only due to the melting of primary or sulfide ores. Consequently, we should reconsider the conclusion that the sulfur impurity has a decisive role in studying the technology of ancient pyrometallurgy.