This duette by Coro is rhodium plated metal with green enameling and white rhinestones. ( some yellowing and some darkened) shaped like bell flowers . The quality is good and the duette flowery subject is good. Coro went on to develop the motif in all possible manners. It is 3 3/8" x 2 3/8".
It appears to me that this item has been repaired. See photos of stem of the duette front and back.
Reference: American Costume Jewelry by Brunialti & Brunialti, v 1 page 111.