Is it permissible to exchange newly minted currency for a lesser amount of broken or cut currency?
Chapter on Riba (Usury) and Exchange (Sarf)
Al-Mughni
Book of Sales
Primary text
It is impermissible to purchase something with broken currency and then pay with whole currency of a lesser amount. Imam Ahmad considers this pure usury (Riba al-Mahd) because one receives less in value for the silver exchanged. Likewise, if one purchases something with whole currency, it is impermissible to pay back with a greater amount of broken currency.