Materials associated with a secondary workshop of early Byzantine date (4th-5th
centuries) were unearthed in excavations by the Israel Antiquities Authority in ‘Aqir, central
Israel. Fragments of furnace structure, production debris and glass vessels have been
analysed by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS)
and thin-section petrography.
The results suggest that the workshop melted raw glass chunks of similar composition to
the primary glass made at Apollonia, Israel, to produce secondary glass products. Some glass
vessels associated with the furnace are of different composition, and some of these may
represent material brought in as cullet for recycling. The furnace was built with ceramic
bricks comprising alluvial-type clay with inclusions of quartz sand, probably added as
temper. It was fired by potash-rich fuel to approximately 1100°C. Lime mortar was used
either to cement the gaps between mudbricks or to line the furnace as a parting layer, and it
has introduced a previously unrecognised type of contamination in glass of the period, mainly
of Fe2O3 and CaO. The contamination may be identified in glass vessel assemblages
elsewhere but is not ubiquitous. As its origin relates to the furnace structure, its occurrence
may depend upon chronology or geography and further work is needed to resolve this issue