ARAB SASANIAN: 'Uthman Ibn 'Affan (644-656), AR Dirham (3.05g), SK (Sijistan), RY 20 (AH 31). Yazdigerd type, the first known Islamic coin. A-1. Extremely fine. Scarce.
The first known Islamic coin, minted during the reign of the Rashidun caliph and Sahabi 'Uthman Ibn 'Affan in the year AH 31. The phrase "bismillah" (in the name of Allah) is added in the second quadrant to distinguish this piece as an Islamic issue apart from the Sasanian coinage.
Estimate: 250-350