Is it permissible to pay an artisan a sum for the manufacture of an ornament, with the remainder to be paid upon completion, knowing that the initial sum paid is not used to purchase gold?

If you are to buy gold from a craftsman and he is to manufacture it, it is not permissible to delay the payment for the gold. Rather, the money must be paid and the gold received in the same sitting. However, the manufacturing fee may be delayed. But if you are to give the gold from your possession to the craftsman for him to manufacture it, there is no harm in delaying the payment of the fee. Sheikh Ibn Uthaymeen clarified that exchanging gold for gold with the addition of a manufacturing fee is prohibited usury (riba), and the correct method is to sell the old gold first, then buy the new gold with the proceeds. It is permissible for the goldsmith to manufacture the gold and collect his fee upon completion of the manufacturing. As for the manufacturing fee, it is not obligatory to pay it upon receiving the gold, as it is for labor.