A Micro-Analytical Study of the Scarabs of the Necropolis of Vinha das Caliças (Portugal)

Abstract

Five scarabs and one scaraboid found in Vinha das Caliças 4 (Beja, Portugal) were analyzed using a micro-analytical methodology in order to determine their mineralogical and chemical composition. Microstructural characterization and chemical analysis revealed that all were composed of a white body of crushed feldspathic sand covered by a lead-rich, alkaline-depleted silicate blue-green glaze showing evident signs of glass deterioration. Variable pressure scanning electron microscopy with X-ray energy dispersive spectrometry, handheld X-ray fluorescence spectroscopy, and micro X-ray diffraction results show that blue-green color of the glaze was produced by using copper ions (Cu2+) in conjunction with the lead antimonate bindheimite, a yellow-colored opacifier. The introduction of small amounts of tin in the structure of bindheimite enabled the production of a ternary Pb–Sb–Sn oxide. Tin, which was most likely added with the copper source (bronze scrapings), is known to facilitate the crystallization of bindheimite. The results are consistent with the five scarabs and one scaraboid being manufactured in Egypt. This study, the first archeometric study of scarabs found in the Iberian peninsula, has greatly contributed to the understanding of the influence of the Eastern and Central Mediterranean world in the Southwestern Iberia during the first millennium B.C.

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

“…Analytical techniques were chosen in accordance with previously published studies of glass beads and other vitreous material from Vinha das Caliças 4 [35,53,66,67] to allow comparison with published results. The procedure included stereomicroscopical examination, micro-X-Ray diffraction (µ-XRD), variable pressure scanning electron microscopy with energy dispersive spectrometry (VP-SEM-EDS), and laser-ablation inductively coupled plasma-mass spectroscopy (LA-ICP-MS).…”

“…Considering no other samples exhibit a noticeably positive Eu anomaly, the peculiar behaviour of these two samples could be influenced by the colouring technology via the same mechanism that impacts Ba and Sr levels, rather than the silica source. Continental barites, aside from occurring in association with galena (PbS), chalcopyrite (CuFeS 2 ), and sphalerite (ZnS), also show positive Eu anomalies [66]. In other words, the positive Eu anomaly might have resulted from the introduction of the same low-grade iron or lead slags used to colour the three samples.…”

Known Glass Compositions in Iron Age Europe—Current Synthesis and Emerging Questions

“…It is definitely interesting to note that only the natron-fluxed glass from the western Mediterranean exhibits unusually high alumina contents [94,95]. It still remains to be seen if this could signify the existence of a Western glass supply chain, because data for Iron Age vitreous materials from the Iberian Peninsula and the islands are overall limited [40,41,[94][95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111][112]. Beads with a high Al 2 O 3 content (3.42-14.41 wt.…”

“…Glass and faience from the western Mediterranean have only recently started to be investigated. Modern-day Portugal is represented by a single 6th century BCE site [40,[110][111][112]. The Spanish territory is somewhat better represented [41,94,95,[119][120][121], but the reliability and usefulness of some older data has been called into question [41,121].…”