Rare Alkali Elements as Markers of Local Glass Working in Medieval Tolmo de Minateda (Spain).

Analytical data of Roman and early Islamic glass established several primary glass production groups linked to glassmaking centres in the Levant and in Egypt. In contrast, the activities of secondary glass workshops are largely invisible in the compositional fingerprint of first millennium glass. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of 261 glass finds from the Visigothic settlement of Tolmo de Minateda (Spain) revealed a site-specific contamination pattern due to secondary glass processing and recycling, namely the enrichment of the glass batch by a unique combination of rare alkali elements (Li, K, Rb, Cs).

Loose glass tesserae and lost decorations: chronology and production of mosaics from Gerasa's Northwest Quarter.

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of loose glass tesserae from the Northwest Quarter of Gerasa/Jerash has enhanced our understanding of the dynamics regulating the production and circulation of glass tesserae in second- to eighth-centuries ce Jordan and the diachronic development of mosaics at the site. The identification of Levantine and Egyptian compositions (Roman-Mn, Levantine I, HIMT, Foy 2.1) proves the continuous production of mosaics from the second to the seventh centuries.

Composition and origins of decorated glass from Umayyad Cordoba (Spain).

Unlabelled: Recent archaeological excavations carried out in the western suburbs of Cordoba (Spain) brought to light numerous fragments of archaeological glass from the caliphal period (929-1031 CE). The typological and compositional analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of 66 fragments enabled the identification of different types of base glass and glass working techniques, identifying local productions, imports and decorative imitations of eastern models. The studied fragments include Mesopotamian, Levantine, Egyptian and possibly Sicilian soda-rich plant ash glass categories, and various glass-decorating techniques such as mould-blowing, pressing, cutting, staining or gilding.

Production and provenance of architectural glass from the Umayyad period.

A large assemblage (n = 307) of architectural glasses (tesserae and windows) from the early 8th-century Umayyad residential site at Khirbat al-Minya was analysed by laser ablation inductively coupled plasma mass spectrometry. Trace element patterns are essential to establish the provenance of the base glass, while the comparative evaluation of the colouring and opacifying additives allow us to advance a production model for the manufacture of glass mosaic tesserae during the early Islamic period. The primary glass types are Levantine I and Egypt 1a, as well as a few older, reused tesserae, and Mesopotamian plant ash glass used for amber-coloured window fragments.

Ex novo development of lead glassmaking in early Umayyad Spain.

This study investigates glass finds from the Iberian Peninsula as a proxy for identifying the mechanisms underlying technological transformations and innovation in the wake of the Arab conquest in the seventh and eighth centuries CE. High-resolution laser ablation inductively coupled plasma mass spectrometry data combined with lead isotope analyses of a precisely dated (mid-eighth century to 818 CE) glass assemblage from the Rabad of Šaqunda in Cordoba, capital of Umayyad Spain, enabled us to trace the origins of an Iberian glassmaking industry and to unambiguously link it to the exploitation of local raw materials. The analytical data reveal increased recycling, some isolated imports of Islamic plant ash glasses from Mesopotamia, and, most notably, the development of a new type of glassmaking technology that resorted to the use of lead slag from silver and lead mining and processing in the region around Cordoba.

The trade of glass beads in early medieval Illyricum: towards an Islamic monopoly.

The trade of glass beads has long been assumed to have been under Islamic dominance during the early centuries following the Arab conquest of the Middle East, judged by the prevalence of Islamic beads in the archaeological contexts from Viking Scandinavia to medieval Morocco. This paper explores the impact of the Byzantine-Slavic transition on the use and by extension trade of glass beads in the Balkans from the seventh to the ninth century CE. A series of 48 glass beads and 4 vessel fragments from two excavated sites in modern day Albania have been analysed morphologically, technologically and chemically by LA-ICP-MS.

The Supply of Glass at (Alicante, Spain): A Meta-Analysis of HIMT Glasses.

Portus Ilicitanus (Picola, Alicante) was the main sea harbour of the Roman Colonia Iulia Ilici Augusta and as such played a crucial role in the supply of fundamental commodities to the Iberian Peninsula. Excavations yielded large quantities of glass in fourth- and early fifth-century contexts. Elemental analysis of 60 samples by laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS) confirmed that the glasses were imported from the Eastern Mediterranean.

Glass import and production in Hispania during the early medieval period: The glass from Ciudad de Vascos (Toledo).

One hundred and forty-one glass fragments from medieval Ciudad de Vascos (Toledo, Spain) were analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The glasses fall into three types according to the fluxing agents used: mineral natron, soda-rich plant ash, and a combination of soda ash and lead. The natron glasses can be assigned to various established primary production groups of eastern Mediterranean provenance.

Comprehensive Chemical Characterisation of Byzantine Glass Weights.

The understanding of the glass trade in the first millennium CE relies on the characterisation of well-dated compositional groups and the identification of their primary production sites. 275 Byzantine glass weights from the British Museum and the Bibliothèque nationale de France dating to the sixth and seventh century were analysed by LA-ICP-MS. Multivariate statistical and graphical data analysis discriminated between six main primary glass types.

Composition, production and procurement of glass at San Vincenzo Al Volturno: an early Medieval monastic complex in Southern Italy.

136 glasses from the ninth-century monastery of San Vincenzo and its workshops have been analysed by electron microprobe in order to situate the assemblage within the first millennium CE glass making tradition. The majority of the glass compositions can be paralleled by Roman glass from the first to third centuries, with very few samples consistent with later compositional groups. Colours for trailed decoration on vessels, for vessel bodies and for sheet glass for windows were largely produced by melting the glass tesserae from old Roman mosaics.

Late Byzantine mineral soda high alumina glasses from Asia Minor: a new primary glass production group.

The chemical characterisation of archaeological glass allows the discrimination between different glass groups and the identification of raw materials and technological traditions of their production. Several lines of evidence point towards the large-scale production of first millennium CE glass in a limited number of glass making factories from a mixture of Egyptian mineral soda and a locally available silica source. Fundamental changes in the manufacturing processes occurred from the eight/ninth century CE onwards, when Egyptian mineral soda was gradually replaced by soda-rich plant ash in Egypt as well as the Islamic Middle East.