Vintage Unmarked Margarita Rivoli Rhinestone Brooch

Beautiful vintage Margarita rivoli rhinestone abstract brooch. Peacock colored rivoli with rhinestones drilled through the center mounted on a filigree base. There are a few nicks on one end under a loop, but there is no peeling or corrosion, so I’m not sure what the metal content is. The soldering on the back doesn’t show any peeling either. Measures about 2 5/16 x 1 5/16”