The working of copper-arsenic alloys in the Early Bronze Age and the effect on the determination of provenance

Abstract

The earliest copper alloy of the British Bronze Age is arsenical copper, a material relatively short-lived when compared with the succeeding tin bronze but of no little importance when tracing the stages and progress of prehistoric metal working. Like tin, arsenic functions as a mild deoxidant and confers the useful property of work-hardening upon the metal. Copper-arsenic alloys need to be strengthened by cold working, and it was probably this requirement as much as any other that would have led to their eventual disuse and replacement by cast tin bronzes. The normal source of arsenic for such alloys is generally agreed as a constituent of the copper ore actually smelted, usually the grey tetrahedrite tennantite mineral (Coghlan and Case, 1957; Tylecote, 1962), although other suggestions have been made (Charles, 1967).