This is a rare and extremely hard to find, hallmarked Child & Child. Child and Child signs their jewelry with 2 C's and a marigold flower. The firm was of the Art Nouveau era and made jewelry for the Queen. It was also very popular with the artistic community from 1890-1930's. You can see pictures and read about the company in Charlotte Gere's book" Pre-Raphaelite to Arts and Crafts Jewelry", pp 56, 135, 44. The locket measures 1 7/8" round with a silver chain. The locket has fabric on the inside for hair or photos. The enamel work is stunning. Condition is excellent.