ARCHAEOMETRIC STUDY OF THE HELLENISTIC METALLURGY IN SICILY: MINERALOGICAL AND CHEMICAL CHARACTERIZATION OF IRON SLAGS FROM PUNIC PANORMOS (PALERMO, ITALY)

Abstract

Archaeological excavations carried out in the town of Palermo revealed important traces of metallurgical

activity related to the Punic Panormos. Five samples of iron slags, recovered during the digging, were char

acterized by micro-structural, mineralogical and chemical investigations as well as by environmental scan

ning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray powder diffraction and X-ray fluo

rescence. The studied remains are spongy, rust colored, with a plano-convex shape and their textural and

mineralogical features suggest they are metallurgical slags produced during smithing process. Wüstite,

magnetite, fayalite, kirschsteinite, hedembergite, cristobalite and quartz are the main identified mineral

phases, while goethite, lepidocrocite and calcite occur as minor secondary phases. The iron slags show het

erogeneous structures such as hammering clues, layering in wustite crystals and presence of calcium-rich

minerals which are consistent with a broad variation of the forging temperature due to the use of different

smithing techniques. This assumption is confirmed by the different crystallization temperatures of the de

tected mineral phases. Skeletal and dendritic shapes are indicative of rapid cooling and, possibly, quenching.

The chemical composition is dominated by iron, silicon and calcium and it is almost constant for all the sam

ples suggesting that they were produced with similar raw materials and technology. The high Ca content

suggests the use of carbonate-bearing rocks, widely outcropping over the Palermo territory, probably ex

ploited as fluxing ores for the metallurgical process. The multidisciplinary approach adopted in this study

provided new data for a better understanding of the metallurgical techniques evolution in the Sicilian terri

tory in ancient times. Since the studied iron slags represent the unique traces so far known of metallurgical

activity in the ancient Palermo town, our results open interesting perspectives for future study of metallurgy

in ancient Sicily.