is this: one counts a single mithqāl—that is, one dinar-weight—as the equivalent of ten dirhams by weight, and regards those ten dirhams as standing in place of the mithqāl.

Example: a man owns one hundred dirhams by weight together with ten dinars; he must pay zakāt on the whole of them. The same applies if he has one mithqāl of gold and one hundred and ninety dirhams by weight: zakāt is due on the aggregate. Likewise, if he possesses nineteen dinars of minted gold and ten dirhams by weight, he is liable for zakāt. I proceed throughout on the basis of this calculation.

In Mālik’s view, for the present discussion and for assessing jizyah, one dinar is reckoned as ten dirhams, whereas in matters of blood-money (diyāt) and marriage settlements it counts as twelve.

A number of scholars in Madinah and elsewhere do not combine dinars with dirhams, nor dirhams with dinars; each must reach its own niṣāb. This is, on reflection, a sound opinion, for the two constitute distinct categories: the prohibition of usury (ribā) does not apply between them, and they may be exchanged in unequal amounts so long as there is no deferment.

Whatever exceeds twenty mithqāls is assessed proportionally: every part of the excess bears its share of zakāt. Thus, on forty mithqāls one pays a single mithqāl, and the same proportional rate applies to every further increase. The rule is identical for anything above two hundred dirhams: zakāt is levied on the surplus in proportion.

If someone owns less than a niṣāb of gold whose market value nonetheless equals the niṣāb of silver—or less than a niṣāb of silver whose value equals the niṣāb of gold—no zakāt is due on either. The same ruling applies to a person who holds fifty dirhams and ten dinars whose combined value amounts to one hundred and fifty dirhams: zakāt is not obligatory for him. And whoever purchases with ten—