Second: The commodity’s genus and variety must be identified, together with the qualities that cause its price to fluctuate.1 The purchaser may accept something inferior to what was originally described, or a different variety so long as it belongs to the same genus.
Third: Its quantity must be fixed by the legally recognized measure. Thus what is normally sold by volume may not be stipulated by weight,2 nor what is normally sold by weight by volume.
Fourth: The item must remain a debt3 until a definite term that people customarily recognize—such as one month—falls due.4
Fifth: It must be of a kind that is usually available5 when the term arrives.
Sixth: The amount of the salam price must be precisely known and firmly delimited; mere inspection is insufficient, and the contract is invalid if the price cannot be exactly determined.6
Seventh: The buyer must hand over the salam price before the two parties disperse from the session in which the contract is concluded. Stipulating the place of delivery is unnecessary,7 for payment is presumed to fall due at the place of contract, unless the agreement was made in open countryside or the like—in which case the place must be specified.
It is invalid to secure the salam commodity itself with a pledge or a guarantor. Should delivery become impossible, the buyer (rab al-salam) may choose either to wait or to annul the contract; if he opts for annulment, he is entitled to the capital he paid, or its equivalent if the original capital is no longer obtainable.