Preliminary Investigation of a metallurgical slag (1st cent. BC) from Grumentum, Basilicata (Italy)

The present investigation focuses on the determination of the morphological, chemical and mineralogical characteristics of an ancient metallurgical iron slag, in order to obtain informations about the metallurgical processes that might have taken place and level earned by local smiths. The slag comes from the forum of the ancient roman city of Grumentum (Basilicata, Italy), on an excavation near the Cesareo temple (1st cent. BC-1st cent. AD). The analysis have showed a different composition and mineralogical structure between the inner matrix, that contains in major percentage maghemite (γ-Fe2O3), wuestite (FeO) and iron fragments, and the surface, made up mainly of goethite (FeOOH) and allumino-silicata of iron. The application of ESEM revealed percentages of Cl in the inner regions and the presence of a crystalline agglomerate identified as monazite (Ce, La, Nd, Th)PO4.