Natural arsenic bronze from the Varten Kamak copper occurrence, SW Bulgaria

In contrast to the traditionally offered methods for metallurgical production of the first bronze for mankind – arsenic bronze, the present study examines another possible natural source of this alloy. Geologically, the only deposit of native copper has been localized near the Varten Kamak hamlet in the area of the town of Boboshevo, SW Bulgaria. Samples of copper nugget were investigated by the methods of powder X-ray diffraction (XRD) and scanning electron microscopy with a microprobe for elemental composition (SEM-EDS). The results show that the analyzed substance is a single-phase solid solution of Cu and As, with As content up to 3.77%, which, according to the accepted nomenclature of archaeometallurgists, is called arsenic bronze. The present study offers a new perspective on the possible sources of arsenic bronze, which may enrich the archaeological sciences.