Unsorted billon (debased silver) Bukhahudat drachms in Fair-F condition. Picked randomly from the group shown - very cheap at only 8$ per coin. The coins are 25-26mm, 2-2.5 grams and all of the type below:
al-Mahdhi behind the bust in Arabic; Bukhar Hudat ("Lord of Bukhara") in Sogdian script in front of the bust, crowned Sasanian-style bust right / Fire altar with ribbons and attendants; crowned bust left in flames. Imitating Sasanian king Bahram V. Album 94.
The issue of these coins took place sometimes around 775 AD, when a group of "notables" in the city of Bukhara approached the local governor, named Ghitrif, complaining about the silver coin shortage in the city and asking to produce a sort of debased fiduciary coinage for local circulation. The governor agreed, and the new coins were commonly called "Ghidrifi" after his name. These new coins were made with the same dies as the old silver issues, but the silver was replaced with an alloy of six metals: gold, silver, lead, brass, iron and copper. Because of their base look, they were not accepted until their price was fixed by law at 6 Ghidrifi drachms to 1 silver drachm of the same type. Interestingly, the coins became very popular and within a short period of time they were at parity with the silver issues. Within 60 years, the price of the Ghidrifi dirhams rose even more, with 100 silver dirhams buying only 85 Ghidrifi dirhams. This was one of the first (and one of the few successful) attempts to experiment with fiduciary coinage in Asia.