Watch List notes:

ABBASID: al-Mahdi, 775-785, AR dirham (2.86g), al-Yamama, AH168, A-215.1, citing 'Abd Allah b. Sa'id, VF, R. The mint of al-Yamima was the only location in what is now Saudi Arabia that was active during the first 70 years of the Abbasid period, only AH165-170.

Estimate: 100- 150 USD