Selective use of arsenical copper during the Mycenaean period: the evidence from Pylia, in Messenia, Greece

Charilaos E. Tselios, Eleni Filippaki & Georgios S. Korres Στο E. Photos-Jones, Y. Bassiakos, E. Filippaki, A. Hein, I. Karatasios, V. Kilikoglou & E. Kouloumpi (eds), 2016. Proceedings of the 6th Symposium of the Hellenic Society for Archaeometry (Bar International Series 2780), Oxford: 81-88.

During the Late Bonze Age tin bronze became the prominent alloy for the manufacture of weapons, vessels, tools and implements in the Greek mainland, as well as in the rest of the Aegean. Apart from a small number of objects dated to the transitional phase from Middle Helladic I, the vast majority of bronze objects that have been examined so far are characterized as tin bronzes. A small number of tin bronzes also contain arsenic as a trace element, usually attributed to the ores or as minor element coming from the recycling of arsenical copper objects of previous periods. Despite this general picture, according to the analytical examination of two bronze artifacts from Pylia in southwestern Peloponnese, arsenical copper was still in use well within the Mycenaean period. In the course of a research project dealing with the study of the Mycenaean metalwork in Pylia, minor samples taken from a battle knife of unknown context from Metaxada, dated to the Late Helladic I or II period and from a razor uncovered in the chamber tomb cemetery at Volimidia, dated to Late Helladic IIIA, were examined under the Optical Microscope and SEM (at N.C.S.R. “Demokritos”). According to the analytical data, the battle-knife consists of a rare Cu-As-Ag alloy, while the tin bronze razor is plated with a thin sheet of arsenical bronze. In both cases arsenical bronze was used well within the chronological borders of the Mycenaean period for aesthetic purposes. In the case of the battle knife, the Mycenaean bronze smith managed, through cycles of hammering and annealing, to take advantage of surface enrichment phenomena in order to manufacture a silver-like of the original tin bronze artifact with a sheet of arsenical copper no more than 10μm thick. Since the two artifacts are dated to different phases of the Mycenaean era, it seems likely that the use of arsenical copper was not restricted to earlier periods and that the Mycenaean metalworkers had never forgotten the properties of arsenical copper and utilized them for limited applications. Moreover, the technical characteristics of die two artifacts reveal the high level of expertise of the Mycenaean bronze smiths who were capable of applying complex and in some cases, sophisticated metalworking practices.