Others permit it, as is the position of Abū Hanīfa and others. The other report from Ahmad permits it if the quantity offered alone exceeds the corresponding quantity accompanied by something else.

With this understood, exchanging debased nuqra silver dirhams for debased nuqra silver dirhams is permissible according to the correct view, just as one milk-producing sheep may be exchanged for another, provided the two are alike in quality or copper content.

As for exchanging nuqra dirhams for black dirhams, if the intention is not to exchange unequal quantities of silver, the copper in the black dirhams is sought in its own right, and these dirhams stand between nuqra dirhams and copper coins. This therefore falls under the well-known disagreement concerning the question of “a mudd of ‘ajwa dates,” since silver and copper are being exchanged for silver and copper, both metals being sought in their own right. The more likely correct view is that this is permissible, as are the other transactions in this category, provided they do not involve prohibited ribā.

The basic principle is to regard contracts as valid, and there is a need for such transactions. As for the hadith concerning beads strung with gold, it was not established that the gold offered separately exceeded the gold accompanying the beads. Valuation of the two different items exchanged was adopted out of necessity.

This applies if the copper can be put to use once separated from the silver. If it cannot be put to use, the transaction is like exchanging silver for silver: equality in quantity is required, and anything whose silver content people cannot ascertain is disregarded. And Allah knows best.