GREAT MONGOLS: Töregene, 1241-1246, AV dinar (2.33g), Dihistan, AH604 (for 640), A-V3750, anonymous, but with the titulature al-khaqan / al-'adil / al'a'zam, without the caliph, mint name above obverse field, date in reverse margin, of which sana arba' wa sitmi'a is clear, VF to EF, RRR. Style and calligraphy place this coin in the late 630s to early 640s, hence 640 most likely, though the date could be an error for 644, also in the reign of Töregene.
Estimate: 700-800 USD