Watch List notes:

ABBASID: al-Ma'mun, 810-833, AR dirham (2.82g), Fars, AH206, A-223.10, cf. Z-130307, double margin both sides, with 'abd Allah 'abd Allah al-imam al-ma'mun amir al-mu'minin in the extra reverse margin, struck only at Fars and only in AH206, bold VF, RRR. This appears to be the earliest regular Islamic precious metal coin to bear double margins on both side.

Estimate: 300-400 USD