According to Wikipedia, The Abbasid Caliphate was the third Islamic caliphate to succeed the Islamic prophet Muhammad. It extended from north Africa, through Egypt and Saudi Arabia, to modern-day Iraq. The Abbasid dynasty descended from Muhammad's youngest uncle, Abbas ibn Abd al-Muttalib, and for most of Caliphate's existence the dynasty ruled from Baghdad. They produced three types of coins: dinar (gold), dirham (silver), and fals (copper). This page applies only to dirham.
Silver Abbasid dirhams weigh around 2.8 grams with diameters around 24 mm. The inscriptions are in Kufic text and usually quote one of the Kalimahs or passages from the Qur'an. There is a good summary of these coins at Forum Ancient Coins.
The dirham in our picture (upper left) comes from Stephen Album Rare Coins where it sold for $140 US dollars during a 2016 auction. Approximate pricing for normal Abbasid dirhams runs like this:
worn: $50 US dollars approximate catalog value
average circulated: $100
well preserved: $200
An expert in such coins (we do not know of one personally, but the forums at World of Coins may help) can identify rare varieties that can be worth more than the prices shown above.
In all cases, dirhams must be free of problems (scratches, stains, cleanings, nicks, gouges, and the like) to reach price levels shown here.