Achates may refer to: Achates (Greek mythology) Achates, name of two ships Achates (river), the Sicilian river known in antiquity as the Achates 5144 Achates, an asteroid Agate, the gemstone called achates by Theophrastus and Pliny the Elder Leonardus Achates, the fifteenth century composer from Basel , the series of British Royal Navy ships named for after this character Achates Power, an American developer of engines