For your consideration is this old and interesting abstract pin. Unmarked but tested as sterling silver with a nice spotted green stone possibly an agate ( not glass) in a nice modernistic design. It reminds me of Betty Cooke and has her great aesthetic style.
It measures 2 and 1/2 inch by 1 and 7/8 inches across the widest points on the pin.
It is in excellent functioning condition. It is quite old and has a heavy uneven patina - circa 1950s I believe.