Gemstones from Vigna Barberini at the Palatine Hill (Rome, Italy)

This study investigates 25 gemstones (23 intaglios and two undecorated cabochon, used between the third quarter of the first century ad and the second century ad) found in the archaeological excavations performed at 'Vigna Barberini', in the north-east sector of the Palatine Hill in Rome. The analytical results obtained by means of SR-XRD, Raman micro-spectroscopy and PIXE measurements provided, in a totally non-destructive mode, unambiguous characterization of the gemstones. The collection from Vigna Barberini consists of two colourless chalcedonies, 11 carnelians, one sard, three Cr-bearing chalcedonies, two nicoli, two orange jaspers, one heliotrope, one almandine garnet, one peridote and one lapis lazuli. Given the lack of analytical data discriminating between different sources, the worldwide occurrence of all these gemstones makes it difficult to reconstruct preferential routes for their commercial trade. However, the methodological approach followed for this research should be of help for the identification of discrimination parameters for provenance investigation.