IIIrd century BC silver coins from Kreshpan hoard (Albania): data form bulk elemental analysis and microstructure studies

N. Civici1,
T. Dilo2,
Sh. Gjongecaj3,
F. Stamati4,
N. Pistofidis5
G. Vourlias5
E. Pavlidou5
G. Stergioudis5
E. K. Polychroniadis5
1Institute of Nuclear Physics, Tirana, Albania
2Department of Physics, Faculty of Natural Sciences, University of Tirana, Albania
3Department of Antiquity, Institute of Archaeology, Tirana, Albania
4Restoration and Conservation Laboratory, Institute of Folk Culture, Tirana, Albania
5Department of Physics, Aristotle University of Thessaloniki, Greece

The Institute of Archaeology in Tirana has a big collection of different types of ancient coins which were found during excavations in the Albanian territory. The majority of the coins were minted by the two big centers of the Illyrian Adriatic coast, Dyrrachion and Apollonia, which have minted bronze and silver coins from the beginning of the IVth century BC.

One of the most interesting groups of coins is the hoard discovered close to the village Kreshpan in central Albania. The hoard contains 209 silver coins, which include staters and half staters with the pattern of suckling cow, minted by the Greek cities of Korkyra, Dyrrachion and by the Illyrian king Monounios, together with quarter of staters with the pattern of Herakles minted in Dyrrachion. The most important findings of the hoard are 45 coins of the Illyrian king Monounios, which illuminate the historical period of the domination of this king in the Illyrian territory and also his relationships with the great centers of the ancient world in the vicinity of Illyria. King Monounios' coins allowed dating of the hoard's burial around 270 BC.

122 coins from this hoard were examined by EDXRF for the determination of bulk elemental composition, while XRD, optical and electron microscopy were used for the investigation of the metallic microstructure of three coins (one from each group).

The compositional results showed that the different groups of coins were made of a similar Ag-Cu alloy with Ag concentration in the range 94 - 98 %. The examination of the contents of minor elements Pb, Au and Bi showed that the coins minted by the Illyrian king Monounios have similar composition with the largest part of Dyrrachion coins and those from Korkyra. On the other side, two subgroups containing different amounts of Au and Bi can be observed within the general group of coins minted in Dyrrachion.

The different microstructure patterns observed from the investigated coins allowed the determination of a possible minting method, which is different for every coin and includes cold-work, hot-work and casting.