Details The classical shape combined with matt black onyx make this ring highly visable and a real statement piece on your finger. Tom Wood signets are made out of solid silver and gold, enabling you to engrave the ring with your own hidden message inside the ring or on the top plate. For rings with onyx on top you should check with a specialist. Make the ring unique and private, like the signet rings once were used. The top plate comes in 16 x 14 mm.