NINMACH 2017

A multi-technique investigation of the incuse coinage of Magna Graecia

11 Oct 2017, 17:40

20m

Hungarian Academy of Sciences

Oral presentation Multi-technique approach and complementary techniques Multi-technique approach and complementary methods 1.

Speaker

Dr Filomena Salvemini (ACNS-ANSTO, Sydney)

Description

This paper presents a synergic combination of different neutron techniques applied to characterize the manufacturing process of ‘incuse’ coins minted by Greek colonies in South Italy during the 6th and 5th centuries B.C. After the invention of coinage in the Asia Minor kingdom of Lydia around 630-620 BC, the manufacture of coins spread all around the Mediterranean. The Greek colonies in Southern Italy developed their own method of minting, the so-called incuse coin technique, around the mid-6th century BC. The distinctive feature of this coin is that the image on one side is repeated on the other side in reverse (or intaglio) – and the alignment is always extremely close. While the production techniques for the coinage minted by the majority of Greek cities on the mainland and in Asia Minor are relatively well understood, the incuse method developed by cities in South Italy is still debated. In order to shed new light on the processes and the advantages of the incuse manufacturing method, a non-invasive multi-technique approach based on neutron imaging and diffraction methods was applied to investigate a set of 30 silver coins produced in the communities of Metapontum, Kroton, Sirinos/Pyxoes, Sybaris, Caulonia and Taras in South Italy. All samples are part of the collection of the Australian Centre for Ancient Numismatic Studies (ACANS), Macquarie University in Sydney (AU). Neutron tomography was exploited to virtually reconstruct the bulk of incuse coins in 3D. It is useful as a means to study aspects such as morphology, porosity, inclusions, the presence of composite structures (plating). Neutron diffraction and SEM-EDS analyses were applied to define their composition. Complementary neutron texture analysis was performed to determine the distinctive texture patterns, the crystallographic preferred orientations in the alignment of the atomic lattice of metal grains induced, by the manufacturing process. This archaeometric investigation is part of the Cultural Heritage project carried out at ANSTO. This scientific program aims to interface and synergize the suite of nuclear methods available across facilities to provide a non-invasive approach for the study and conservation of heritage materials. In close collaboration with the cultural heritage community, the research is focused on several areas ranging from the characterization of Aboriginal pigments, through the chronology, origin and conservation of Australian Rock Art, to the study of archaeometallurgy.