Watch List notes:

ISLAMIC, 'Abbasid Caliphate. temp. Al-Ma'mun. AH 194-218 / AD 810-833. AR Dirham (24mm, 2.94 g, 12h). Citing Tahir. al-Rafiqa mint. Dated AH 197 (AD 812/3). Cf. Lowick 647 (AH 199); Album 223.4; ICV 390. Darkly toned, slight double strike on reverse. VF. Rare.