Loose glass tesserae and lost decorations: chronology and production of mosaics from Gerasa's Northwest Quarter.

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of loose glass tesserae from the Northwest Quarter of Gerasa/Jerash has enhanced our understanding of the dynamics regulating the production and circulation of glass tesserae in second- to eighth-centuries ce Jordan and the diachronic development of mosaics at the site. The identification of Levantine and Egyptian compositions (Roman-Mn, Levantine I, HIMT, Foy 2.1) proves the continuous production of mosaics from the second to the seventh centuries. The Levantine I tesserae were made by the recycling and colouring of glass cullet. The gilded tesserae, in contrast, were all of an Egyptian base glass, likely illustrating the import of finished tesserae.