Characterisation of Byzantine and early Islamic primary tank furnace glass

Abstract

In order to improve the understanding of glass production and provenance, we present trace element and Sr, Nd and B isotope ratio data for 15 samples of raw natron glass from a single tank furnace in Apollonia (6 th -7 th century C.E.) and eight glass samples from two tank furnaces in Bet Eli'ezer (8 th century C.E.) in Israel. This data provides information about the geochemical homogeneity within a single batch of raw glass and about the differences and/or similarities between different tank furnaces on a single site. Four glasses from a secondary workshop at Tell el-Ashmunein, Egypt (8 th -9 th century C.E.) are analysed for comparative purposes. All raw glass samples have uniform trace element patterns and ratios. Because of poor mixing of the glass batch before and during firing, absolute concentrations however can vary significantly within a single tank furnace. The concentrations of trace elements commonly associated with (de)colouring are very low and can be attributed to background concentrations in the sand raw materials. This indicates that there was no obvious recycling of glass cullet at this stage of the production process and that the tank furnace glass is primary glass in the true sense of the word. The isotopic compositions of Sr, Nd and B in the tank furnace glasses are relatively homogeneous. This confirms their potential as provenance indicators. The isotopic composition of Sr in tank furnace glass from Apollonia and Bet Eli'ezer indicates that the lime was derived from seashell, suggesting the glass was produced from beach sand. Glass from Tell el-Ashmunein contains Sr with lower 87 Sr/ 86 Sr ratios, pointing to the use of limestone as the source of lime. All primary glasses from Israel analysed have Nd isotopic compositions typical for an Eastern Mediterranean origin. δ 11 B indicates that natron used in the tank furnaces in Apollonia and Bet Eli'ezer was most likely imported from Egypt. HIGHLIGHTS Trace element and Sr, Nd and B isotopic characterisation of primary tank furnace glass  Provenancing raw materials used in the production of primary glass  Geochemical homogeneity within a single batch of raw glass  Differences and similarities between tank furnace glass on a single site

Geochemistry of Byzantine and Early Islamic glass from Jerash, Jordan: Typology, recycling, and provenance

“…The implication is that, whereas the Apollonia‐type glasses from Jerash show features fully consistent with a single primary production, there has been significant recycling and this is reflected in the colorants. Furthermore, analysis of glass from tank furnaces on the Levantine coast indicates Pb values typically less than 10 ppm, and Cu values less than 5 ppm (Brems et al., in press; Phelps et al., ), whereas with only one exception, our Apollonia‐type glasses contain higher levels (Table ) suggesting that the great majority of the Apollonia‐type glass analyzed here contains some recycled material.…”

“…3; Table 4). Apollonia data from Brems et al. (in press) [Color figure can be viewed at wileyonlinelibrary.com]…”

Chemical Characterization of Vitreous Finds from Cosenza Cathedral (Calabria – Italy) by the Combined Use of Analytical Techniques

“…The glasses of the subgroup 1B show chemical characteristics that can be related to the HIMT2 type. Bibliografic data from: Brems et al, 2018;Ceglia et al, 2015Ceglia et al, , 2019De Juan Ares et al, 2019a;Foy et al, 2003;Gliozzo et al, 2019;Phelps et al, 2016;Schibille et al, 2017Schibille et al, , 2019 Indeed, differing from the HIMT1 glasses, the samples show lower contents of FeO, TiO 2 and Mn. Furthermore, CaO and Al 2 O 3 contents vary around 7-8 wt% and 2.5-3 wt% respectively.…”

“…In terms of the major element concentrations generally observed in the glasses of the Roman and early medieval periods, Freestone's (2005) pioneering paper distinguished 5 natron-types glasses: Levantine I, Levantine II (produced using coastal sand of Siryo-Palestinian region), Roman blue-green, HIMT (High Iron, Manganese, Titanium) and Egyptian. The Levantine I glass was produced at Jalame (from 4 th century AD) and Apollonia (from 6 th to and 7 th century AD), while the Levantine II glass was produced at Bet Eli'ezer, near Hadera, Israel during the 8 th century (Brems et al, 2018;De Juan Ares et al, 2019b;Phelps et al, 2016). Then later the Levantine group (Gliozzo, Braschi, Giannetti, Langone, & Turchiano, 2019) has been related to the Foy's "Group 3.3" (Foy, Picon, Vichy & Thirion-Merle, 2003).…”

“…With the aim of evaluating the attribution to the Levantine I or Levantine II, the US122-75 glass has been compared with the bibliographic data (Brems et al, 2018;Ceglia et al, 2015;Gliozzo et al, 2019;Phelps et al, 2016;Schibille et al, 2017) by using the diagram proposed by Phelps et al (2016). The diagram ( Figure 6) highlights the similarity between the US122-75 sample and the Jalame-Levantine I source dating to the 4 th century AD.…”