If gold is sold for gold directly, it must be equal in weight; otherwise, it would be usury. This issue can be resolved by purchasing the gold initially from the customer, for example, and determining the amount for them, then selling the gold to the customer and specifying the amount, after which the difference between the two is paid either to the seller or the buyer. However, it is a condition in this process that the bodies of both the seller and the buyer do not separate until everything is completed; because one of the conditions for selling gold is the receipt and delivery in the same session, otherwise they would fall into usury.