<p>Slumped bowls from Tell Iẓṭabba pre-date the site’s destruction in 107 BCE, allowing for investigation of Hellenistic translucent glass with a terminus ante quem. LA-ICP-MS of thirty shards reveal two groups. While IZT-2 glasses correspond to Levantine glass of the Roman period, IZT-1 glass has lower Al₂O₃, MgO, FeO, Ti and higher ε_Hf at a given ⁸⁷Sr/⁸⁶Sr value. Attention is drawn to the decline in Al₂O₃ contents of known primary glass production from South to North on the Syro-Palestinian coast. Based on this, it is suggested that IZT-1 glass originated north of Beirut. Colourless glasses typically contain both manganese and antimony. It appears that antimony was added to glass already containing manganese to improve the colour. Hence the assemblage provides insights into two important technological changes that underpinned the early Roman expansion in glass production of the period – a shift in the location of production and the development of decolourisation.</p>