antique cast metal filigree rosette, hardware for wall or ceiling mount gas light lighting fixture

Early 1900s vintage cast metal rosette medallion for a light fixture, probably a gaslight, I think. This is very ornate, beautifully detailed brass or spelter metal with original old gold finish (somewhat discolored, tarnished, and spotted with old paint).

The center mounting is a 3/8" lamp thread, though you could probably drill this out, or use an adapter to change the size if you want to. There's no chips, cracks or breakage to the metalwork that I could find.