ACHA´TES(Ἀχάτης), a small river in Sicily, noticed by Silius Italicus for the remarkable clearness of its waters (perlucentem splendenti gurgite Achaten, 14.228), and by various other writers as the place where agates were found, and from whence they derived the name of lapis Achates,which they have retained in all modern languages. It has been identified by Cluverius (followed by most modern geographers) with the river Dirillo, a small stream on the S. coast of Sicily, about 7 miles E. of Terranova, which is indeed remarkable for the clearness of its waters: but Pliny, the only author who affords any clue to its position, distinctly places the Achates between Thermae and Selinus, in the SW. quarter of the island. It cannot, therefore, be the Dirillo, but its modern name is unknown. (Plin. Nat. 3.8. s. 14, 37.10. s. 54; Theophrast. de Lapid. § 31; Vib. Seq. p. 3; Solin. 5.25; Cluver. Sicil. p. 201.)
[E.H.B]