Thirteenth century hard stone cameo, probably South Italian/ Sicilian / ca 1260-1280.
For similar examples see Hohenstaufen gems.
Medieval cameos are very rare. The few medieval carvers active in the fifteeth century were copying ancient Roman gems, with verious degree of success.
The cameo is in a worthless silver pin ca 1800
Measurement of cameo without the silver surround:18 x 14 mm