Vintage cameo with enameling retailer 3-1-21B

this cameo is surrounded by gold, black and white enameling which really sets it off The gold toned metal surrounding the actual black cameo is worn in spots but you cannot see it. It measures 1 5/8” long by 1 1/4” wide. It retailer is unmarked aside from the pat.l # for the pin back
It is really an eye catcher.