Contribution à l'étude des verres antiques décolorés à l'antimoine

Abstract

Among the different compositional groups of Roman glasses, one group of unknown origin is characterized by low levels of aluminium, magnesium, iron and phosphorus as well as by the use of a decolorizer : antimony (compositional group 4). This compositional group was first identified in Great Britain. The results of our analyses undertaken on the cargo of a shipwreck and on a lot of samples coming from numerous Mediterranean sites but also from two secondary workshops in Gaul reveal/show the same composition or variants. The latter may be due to multiple origins, which still has to be proved. But they would rather be due to natural variations within the sands of a same area or to pollutions or mixtures caused by the remeltings in the secondary workshops. This compositional group, named group 4, is important mainly in the 2nd century AD and in the beginning of the 3rd century AD. Its existence means that others production centres of perfectly colourless glass seriously competed with the production centres of the syro-palestinian coast, which up to this period had almost the monopoly of glass trade towards Occident.

Compositional Variation in Roman Colourless Glass Objects From the Bocholtz Burial (The Netherlands)*

“…A comparison with literature data from other closed finds from the same period is made in Figure 5: the data used came from the Ouest Embiez I shipwreck off the coast of Toulon (Foy et al 2003, 2004) and the Iulia Felix shipwreck off the coast of Grada (Silvestri et al 2005b). Both are dated to the late second to early third century—like the Bocholtz burial.…”

“…However, such data were not available to us. As an alternative, we made a comparison with several published data sets on Roman colourless glass from different sites in England, France, Italy and the rest of the Mediterranean (data from Foy et al 2004; Jackson 2005; Silvestri et al 2005b; Paynter 2006). This does not cover all published data sets of Roman colourless glass; if such a comparison were to be made, the data sets of Baxter et al (1995, 2005) would certainly need to be included.…”

“…Also, the use of cullet (recycled waste glass) was probably very limited (Jackson 2005). This makes colourless glass a very suitable material for the study of production, transport and trade in the Roman world on the basis of source‐related compositional variation (Foy et al 2004; Baxter et al 2005; Sylvestri et al 2006).…”

“…Also, Strabo and Pliny mention the Levant (especially the Belus river sands) as a major source for glass (Humphrey et al 1998). However, according to Foy et al (2004), the large compositional homogeneity in second and third century ad antimony‐decoloured colourless glass (‘group 4’) is caused by one or more workshops outside the Syro‐Palestinian production centres seriously competing on the glass market, ending a Levantine monopoly of glass trade towards the western parts of the Roman Empire. Silvestri et al (2006) suggest—on the basis of texts by Pliny the Elder and geochemical research—that at least some of the primary colourless glass was produced in the south of Italy, with sands derived from the Campanian beaches around the mouth of the Volturno river.…”

“…However, it could also point to changes in a single source on short time‐scales. Most chemical provenance studies are constrained by a time‐line based glass objects type‐chronology (e.g., Foy et al 2004; Baxter et al 2005; Paynter 2006). Since these dates often have a time‐resolution of > 100 years, it is impossible to determine whether or not the objects studies were ‘on the market’ at the same moment.…”