Ancient gold metallurgy and the colour characteristics of gold alloys are well researched, but the same has not previously been true for the most abundant type of metal artefacts in prehistory - copper alloys such as tin bronzes, or arsenical copper.
     Following the discovery of the world's earliest tin bronze artefacts four years ago in Serbia, the ongoing debate into what significance colour played in the advancement of metal technologies, and inspired by modern jewellery making where colour charts are used to explore properties of gold-copper-silver alloys, an international team of researchers replicated the most common prehistoric copper alloys, revealing the original colours of ancient artefacts.
     Serbian team leader Professor Zeljko Kamberovic from the University of Belgrade Faculty of Technology and Metallurgy says: "Our laboratory is one of the few in Europe to hold a license to experiment with arsenic, which is why we were approached to develop the study and produce 64 metal samples of variable copper-tin-arsenic compositions."
     Professor Martinon-Torres from the University College London Institute of Archaeology, where chemical and colorimetric analyses were conducted, says the research presents a valuable study of colour of the most commonly produced prehistoric alloys worldwide, demonstrating the original shine of artefacts.
     Doctor Miljana Radivojevic, the study's lead author and a researcher with the McDonald Institute for Archaeological Research, at the University of Cambridge, England, says the charts enabled the team to evaluate claims that early tin bronzes in the Balkans had a distinctive golden hue, and believes it is "now highly likely that the production of this new alloy in the Balkans at the same time as gold could have been dictated by the demand for the 'exotic' golden hue, or its closest imitation". Doctor Radivojevic anticipates the charts being widely used in teaching and museum exhibits.

Edited from EurekAlert! (21 December 2017)