Retailer Coro door knocker brooch book piece!

Coro door knocker brooch bookpiece with gemstones in gorgeous condition. Its actually a miniature door knocker signed in script Coro. The design is art nouveau with leaves and turquoise stones, rhinestones, and a garnet colored cab in gold plate retailer vermeil. Featured in Marcia Browns book on Coro jewelry. All stones intact, plating in very good vtg condition. Thank you