A glass workshop in ‘Aqir, Israel and a new type of compositional contamination

Islamic Glass in the Making

“…Hence, the strontium isotopic values are consistent with Holocene seashell being the main source of lime in these Roman glasses (Brems et al 2018;Freestone et al 2003a;Freestone et al 2009a). The minor variations in the strontium isotope data may be attributed to slightly different proportions of limestone and seashell in the sand source Freestone et al 2003a;Freestone et al 2009a) and/or contamination by the furnace environment (Brems et al 2018;Chen et al 2021). The neodymium isotopic ratios (ε Nd ) range from -6.6 to -3.8 (Fig.…”

“…The al-Raqqa glasses tend to have somewhat higher lime and lower soda levels than the glass from the primary furnaces at Apollonia. The lime lining of glass furnaces can occasionally contaminate the glass batch and thereby augment the lime concentrations (Chen et al 2021), while prolonged or repeated heating can result in the loss of sodium (Freestone 2015). It is likely that cullet was the main raw material for further processing at al-Raqqa, and we can assume that glass cullet and raw glass derived from more than one primary production site (Henderson et al 2005b).…”

Chemical analyses on late antique glass finds from Histria, Romania

“…More precisely, these fragments can be identified as products of Apollonia primary workshops, topic recently reviewed by Freestone (2020). Their most striking feature is the extremely high lime content ($ 11.22 wt% CaO) most likely resulting from furnace contamination and repeated recycling, as explained by Chen et al (2021). These samples are also characterized by low soda ($ 14.60 wt% Na 2 O), iron ($ 0.49 wt% Fe 2 O 3 ), manganese ($ 0.03 wt% MnO), and titanium ($ 0.09 wt% TiO 2 ) concentrations.…”

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

“…[12][13][14][15][16][17][18][19] These phenomena have been increasingly investigated in recent years in order to understand better differential glass working processes and supply chains. [12][13][20][21][22][23][24][25][26] The study of debris and associated materials from secondary workshops in well-defined contexts promises to reveal local variations and practises. [27] The present article addresses issues of glass supply and recycling in early medieval Spain through large-scale trace element profiling, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of early medieval vitreous materials from a secondary production site at El Tolmo de Minateda.…”

“…Glass is subject to changes in composition caused by secondary production due to contaminations from fuel ash and/or colouring elements that were incorporated into the batch and the loss of volatile elements at high temperatures or prolonged heat treatments [12–19] . These phenomena have been increasingly investigated in recent years in order to understand better differential glass working processes and supply chains [12–13,20–26] . The study of debris and associated materials from secondary workshops in well‐defined contexts promises to reveal local variations and practises [27] …”