The heavy, central knot of glass left on a piece of crown glass after it is spun flat and snapped off the punty iron. In traditional window glass making, this thick center was often cut out and used for cheaper glazing. It is characterized by its concentric rings and the rough scar where the iron detached.
Heard on the job
The client wants authentic crown glass for the restoration, complete with the bullion in the center panes.
Also heard as
- bullseye
- crown
Do not mix it up with
- Pontil mark: A pontil mark is the rough scar left on the base of any blown vessel, while a bullion specifically refers to the thick center of spun crown glass containing that scar.