BI Dirham - Al-Mustansir Billah

According to Stephen Album (Checklist of Islamic Coins 3rd Edition):
Silver and billon types of this reign vary from region to region,
with a great diversity of local types. Although some series seem
at least vaguely to preserve some sort of weight standard, most
were struck at random weights. By the end of the reign, the silver
content was typically 25% or less, and the coins have a blackish
color, for which they appropriately came to be known as the black
dirham, dirham aswad.
Sur and ‘Akka are the only mint names occasionally seen (R); all
others are at least very rare. The great majority of these
“dirhams” lack both mint and date