Georgian topaz, garnet and pearl 15 carat gold  ring dated 1818.
Inscribed to the underside of the bezel ‘Meae Carissima Sirena’ 1818.
The literal Latin translation would be ‘My Dearest Mermaid’ but possibly Sirena is simply the name of the recipient.
This unusual ring is likely a sentimental gift to a loved one.
Size 8.