18k & silver ancient greek coin pendant with hercules / athena, 380-281 bc

Lola Brooks 18k yellow gold & Ancient Greek Hercules / Athena coin pendant, 380-281 BC. The coin features Hercules holding a club, with his arm draped with a lion skin on one side, and Athena in a crested Corinthian helmet on the reverse. The pendant measures approximately 1″ x 7/8″, and it hangs from a 20″ long 18k yellow gold chain.