Analyzing the structure and chemical composition of an Etruscan bronze fibula from Tomb Number 129 at Vulci (VT, Italy) through a non-destructive multi-analytical approach

This study examines an Etruscan bronze fibula dating back to the 8th century BC, which is part of the grave goods found in tomb number 129 from the Archaeological Park of Vulci (VT, Italy). The investigations were conducted using a multi-analytical approach based on non-destructive techniques, i.e., Energy Dispersive X-ray fluorescence (ED-XRF) combined with Monte Carlo simulation (MCS) (Golosio et al., 2014), micro-Raman spectroscopy, and X-ray microscopy (XRM). The results revealed that the fibula was produced in a single casting event with a ternary Cu-Sn-Pb alloy. XRM enabled 3-D reconstructions of the fibula, which allowed the investigation of its internal structure (Bernabale et al., 2023), production technology, and preservation state by distinguishing the metal core from the corrosion layer and highlighting areas of fragility. The patina was evenly and compactly distributed over the entire surface, with a thickness between 100 and 400 µm. Micro-Raman spectra indicated the presence cuprite (Cu2O), malachite (Cu2CO3(OH)2), brochantite (Cu4(OH)6SO4) and sampleite (NaCaCu5(PO4)4Cl•5H2O). These latter two phases were also found in another tomb under similar environmental conditions. Indeed, the formation of sampleite and brochantite is promoted by the presence of bacteria and organic matter within burial environments (Muros & Scott, 2018).