Looking closer.....my (amended guess is it's a silver Abbasid dirham from after 750 AD. The obverse reads: "There is no diety excetp (the one) God alone. He has no equal". Also: "In the name of God. This dirham was struck in (location of mint) in the year (written out). The reverse reads (in the central legend) Muhammad the Messenger of God." Then: "Muhammad is the messenger of God. He sent him with guidance and the true religion to reveal it to all religions even if the polyetheists abhor it."
Don..