This unusual 'double' ring rotates, so that Apollo or his lyre can be uppermost.
The original coin, dating from ca 395-392BC is a silver tetradrachm from Olynthos in Chalkidiki in northern Greece.
The cities of Chalkidiki in the northern Aegean, among them Olynthos, Mende and Potideia, were founded as colonies by the city of Chalkis on the island of Euboia. The coin reads 'Chalkideon' (of Chalkidiki).
Laureate Apollo, with his signature wreath, is depicted on the side. He was the verstile god of the sun, light and progress, culture and the arts, music, poetry, medicine, healing, prophecy and oracles.
The lyre is a kithara type, with seven strings. Hermes, who according to mythology invented the lyre with three strings, gave it to Apollo, who added another four.