and likewise anything whose edible portion remains inside its peel, as well as grain that has hardened while still in its ear.

The price, moreover, must be clearly known. Thus, if a man sells an article “at its cost price,” or for “one thousand dirhams in gold and silver,” or “for whatever price the market settles at,” or for the price at which Zayd sold it1 while both parties—or even just one of them—do not actually know what that price is, the sale is invalid.

If, however, he sells a piece of cloth, a heap of grain, or a flock, stipulating that each cubit, each bushel, or each sheep is for one dirham, the sale is valid. By contrast, if he sells from the heap saying, “each bushel for one dirham” or “for one hundred dirhams except one dinar”—and the converse—or if he sells something of known quantity together with something of unknown quantity2 that cannot be ascertained, without saying, “each of them is for such-and-such,” the sale is void. Should it be possible to ascertain the unknown, the sale stands with respect to the known portion in proportion to its share of the price.

If3 a person sells an undivided share that he owns jointly with another—such as a slave, or any property whose price can be divided by parts—the sale is valid for his own share at its corresponding portion of the price. Likewise, if he sells his own slave together with someone else’s slave without that person’s permission, or a slave together with a free man, or vinegar together with wine, all in one transaction, the sale is valid for his own slave and for the vinegar in proportion to their share of the price; but the purchaser has the option to rescind if he was unaware of the circumstances.

Section
A sale concluded by someone upon whom the Friday prayer is obligatory, after the second call to prayer, is invalid; marriage contracts and all other agreements remain valid.

It is also invalid to sell freshly pressed juice to someone who will make it into wine, to sell weapons during a time of civil strife, or to sell a Muslim slave to a non-Muslim when that sale would not result in the slave’s emancipation; and if the slave embraces Islam while in the buyer’s possession, the buyer is compelled to remove it.