An Archaeometric Analysis of Black-Appearing Iron Age Glass Beads from Vinha das Caliças 4 (Portugal)

Phoenician colonisation of the Iberian Peninsula in the 1st millennium BCE introduced many novel and luxurious goods to the local populations of the Western Mediterranean. Among them, black-appearing glass beads are characteristic of indigenous female burials in Southern Portugal during the 6th century BCE. This study presents the results of the first comprehensive archaeometric investigation of black-appearing glass from Vinha das Caliças 4 (Portugal), and of black-appearing glass from the Iberian Peninsula in general. A multi-analytical approach employing Stereomicroscopic observation of manufacture and use traces, VP-SEM-EDS, μ-XRD, and LA-ICP-MS was used to cover a wide range of questions regarding technology and provenance. All analysed samples are natron glass. All samples of black and white beads are characterized by high Zr and low Sr values typically ascribed to the use of Egyptian sands. A comparison of the results of previous studies from the same site clearly demonstrates at least two geochemical provenances for Phoenician-traded glass beads, located in the Levantine region and Egypt, respectively. Furthermore, different colours of glass in individual polychrome beads exhibit similar trace element patterns, which might suggest these beads could have been produced close to glassmaking sites/regions.