An IBA multivariate-driven provenance investigation of ancient lapis lazuli amulets from the Museo Egizio (Turin, Italy)

In this study, 12 selected carved lapis lazuli amulets from various periods of ancient Egyptian history, from the New Kingdom to the Graeco-Roman Period, were analysed non-invasively to determine the provenance of their raw material. The amulets are part of the Museo Egizio of Turin (Italy) collection and include five samples retrieved at the ancient site of Heliopolis (Egypt). To ascertain the lapis lazuli provenance, in-air ion beam analyses (IBA) were employed to measure trace element content and luminescent properties of the various mineral species within the rock (diopside, pyrite, and calcite). Results were compared with those from a large set of reference rocks (almost seventy samples) from five mining areas in present-day Chile, Afghanistan, Siberia, Tajikistan, and Myanmar. Multivariate statistical analysis, in particular principal component analysis, was largely employed to drive the provenance assessment. The results enabled clear provenance identification in most cases. It has been demonstrated that the lapis lazuli of 10 amulets originated from Afghan quarries, reinforcing the archaeological hypothesis of a continuous primary supply of Egypt from this region during the II-I millennium BCE. This result is particularly significant for the Heliopolis amulets, which are among the few Egyptian lapis lazuli artefacts from a known archaeological context analysed in literature for provenance studies. The remaining two amulets show more complex but potentially interesting results, especially an amulet from the Graeco-Roman Period that seems to be a rare example of carved object from the Mediterranean area whose raw material does not show chemical–physical compatibility with the Afghan source. This work represents one of the few provenance studies to include such a significant set of lapis lazuli artefacts associated with the material culture of ancient Egypt, spanning different historical periods, and systematically compared with a large database of geological reference rocks.