SAFAVID: Tahmasp I, 1524-1576, AV unit (2.57g), Tabriz, ND, A-2592F, hexafoil // square, very rare denomination, probably the short-lived issue circa AH935-937, as the type was found in the hoard that terminated with the year 938, VF, RRR. Only 1 example is on CoinArchives, none in Zeno and none in the Tübingen collection. The name of this denomination is unknown.
Estimate: 300-400 USD