This is a wonderful vintage Art Deco dress clip made of sterling silver and set with onyx and chrysoprase (or chrysophase) in a geometric machine age design. The stones have been tested with a gemstone tester and it is marked Sterling on the back.
These old dress clips can be used as intended in the neck of a dress or blouse, or you can easily slide a chain through the back and wear them as a pendant.
It is a small size measuring 1 1/4 inches by just barely under 1 inch. It is in very nice condition. The clip mechanism works well and there is no visible damage.