The coloured glass of Iulia Felix

Abstract

Research on the cargo of glass in the Roman ship Iulia Felix, wrecked off the town of Grado (province of Udine, North Italy) in the first half of the 3rd century AD and composed of recycling cullet carefully selected for colour and type, provided much information on Roman glass production technology. A combined approach, involving analytical, statistical, and archaeological evidence, included chemical analyses (X-ray fluorescence, electron microprobe), which indicated that the coloured samples were all soda-lime-silica in composition, with natron as flux, although cluster analysis identified many compositional groups. Comparisons among the compositional groups of the colourless glass, previously studied, and those of coloured glass showed that the production technologies of the colourless glass vessels constitute two well-defined technological end-members, also related to group types, into which those of the coloured glass samples fall. In particular, coloured glass samples - all bottles, low-status vessels - were produced with mainly beach siliceous-feldspar-calcareous sand. However, unlike the colourless type, strict control of raw materials and decolourising processes was not adopted, and recycling was also practised, as demonstrated by the Sb2O3, Cu and Pb patterns. In this context, a ‘‘recycling index’’ (RI) - [(Sb2O3)X/(Sb2O3)Ref]*100 - proposed here for the first time, in order to quantify the extent of recycling of antimony colourless glass in the batch. RI is valid for glass containing abundant Sb from an end-member of colourless glass. In conclusion, although it cannot be stated unequivocally that the identified compositional trends are related to different production centres or different raw materials, the strong evidence of compositional variability among all the Iulia Felix glass samples, both colourless and coloured, supports the dispersed production model for Roman glassware and the common practice of recycling in Roman imperial times, especially for low-status vessels

Glass Making in the Greco-Roman World: Results of the ARCHGLASS project

“…The Roman glass workshops of Western Europe are far more common and often better documented than those of the Eastern Mediterranean (Stern, 2002), but even without the secondary workshops, there is strong evidence for glass production and trade. For example, Roman shipwrecks such as the Embiez or the Iulia Felix have been found carrying cargoes of glass and glass cullet (Silvestri, 2008). Shipwrecks along the coast of Israel have also been found carrying raw chunk glass, indicating trade by sea existed (Gorin-Rosen, 2000).…”

Pattern in Glass Use in the Roman and Byzantine Worlds: A Report on Current Research at the Institute of Archaeology and UCL Qatar

“…In addition to the shipment of raw glass, individual artefacts or sets of vessels also moved long-distance, for instance as gifts, as containers, as souvenirs or specialist trade items. Finally, there was a lively market for recycled glass, as evidenced from the cargo of shipwrecks (Silvestri et al 2008) as well as from historical sources.…”

Ancient Glass: A Literature Search and its Role in Waste Management

“…Thus, while reducing, it contains no silica. Despite the similarity of the compositions of these glasses (Silvestri 2008;Silvestri, Molin, and Salviulo 2008), the layers on the surface of these glasses are different for the colored and colorless glasses with a multilayer sequence of lamellae on the colored glasses and a white amorphous layer on the colorless glasses (Silvestri, Molin, and Salviulo 2005a). It is unclear why these differences in dissolution occurred.…”

“…Verney-Carron et al 2009; Aurélie Verney-Carron et al 2010; Aurelie Verney-Carron, Gin, and Libourel 2008;Frugier et al 2009;Frugier et al 2008) and the group at the University of Padova, Italy (Longinelli et al 2004;Salviulo et al 2004;Silvestri 2008;Silvestri, Longinelli, and Molin 2010;Silvestri, Molin, and Salviulo 2005a;Silvestri, Molin, and Salviulo 2005b;Silvestri, Molin, and Salviulo 2008;Silvestri et al 2006;Benedetti et al 2007;Dal Bianco and Bertoncello 2008; …”