Roman Glass‐making at Coppergate, York? Analytical Evidence for the Nature of Production*

Abstract

Ceramic vessels and associated vitreous debris, excavated at Coppergate, York, UK, have been interpreted as the remains of Roman glass-making from the raw materials. This paper reports the results of analysis of this assemblage by XRF, ICPS, XRD, SEM-EDAX and thin-section petrography. These findings suggest that some ceramic vessels, used as crucibles, have been subjected to temperatures up to 1200 ° C, well above the firing temperatures of the local domestic assemblage from which they were selected. Analysis of quartz-rich debris, intimately mixed with glass in some samples and in others interleaved with glassy phases, indicates partially reacted glass-making raw materials, with α -quartz, tridymite and cristoballite phases represented. This could represent evidence either of a failed attempt to frit the raw materials, or a batch that had not fully fused. Variability in the composition of glass at the site is viewed in the light of glass-making technology, and possible interpretations concerning this episode are discussed in the light of the archaeological evidence.

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

“…Likewise, it is assumed that each raw material has an individual geological signature, for example, sand sourced from Italy will have a different signature to sand sourced from Israel. The glass manufacturing and working processes can also leave a signature in the finished product, for example, glass can be contaminated by the crucible material (Jackson et al, 2003b). Since the chemical properties of an object are seen as characteristic of the raw material source, the composition of the artefact is effectively a 'chemical fingerprint' (Wilson and Pollard, 2001).…”

“…The second method uses the fundamental geological properties of the artefact to predict a potential origin in the absence of comparative material (Freestone et al, n.d.). The former method relies on the existing chemical and isotopic data collected from various Roman glass assemblages, such as the composition of glass collected from the Roman furnaces in Egypt (Nenna et al, 2000); the small scale production from York, England (Bingham and Jackson, 2008;Jackson et al, 2003b); or the detailed evidence from the 4 th century glass possibly made at Hambach, Germany (Wedepohl and Baumann, 2000;Wedepohl et al, 2011a); as well as the detailed studies undertaken on 4 th -5 th century HIMT glass and 4 th -8 th century Levantine glass (Freestone, 2001;Freestone et al, 2002b). The second method utilises isotopic studies, particularly of Sr and Nd, to infer the likely locations of glassmaking sands and therefore the location of the primary furnaces in which the raw glass was made (Freestone et al, n.d.).…”

Analyses of colourless Roman glass from Binchester, County Durham

“…Relatively few chemically distinct glass compositional types have been identified from this period and this, together with the archaeological evidence, supports the ''large scale, few sites'' model of glass production. In contrast, little archaeological evidence has been identified of primary glass production in the 1ste5th centuries AD, although glass working evidence from Coppergate, York, and Hambach Forest, Germany, has been interpreted as possible exceptions [14,32]. The compositional data for the Binchester glass assemblage have the potential to illuminate this period of glass production, particularly if compared with the results for similar assemblages from elsewhere in England, for example Lincoln and Colchester [1,4,19], and the Roman world.…”

A geochemical study of Roman to early Byzantine Glass from Sagalassos, South-west Turkey

“…Additionally, the basic glass raw materials of soda-lime-silica glass are by nature not exceptional materials, not at all restricted to the mentioned core area, or even to the eastern Mediterranean or the Roman Empire. Admittedly, the quality and the combination of the available raw materials may not always be as pure or ideal as the Belus river sand and the natron from Egypt, but may have met the needs, as illustrated by the case of Roman York [20,21,33] and the late Roman Rhineland [43], where local primary glass production was suggested. The available studies form a sound basis for the hypothesis of this organisational distinction, but the fact that a fairly restricted set of primary production centres within one or other region would approach a near-monopoly of providing the rest of the empire with fresh glass contradicts our reconstruction of the ancient economy.…”