Is buying a gold necklace by selling two gold bracelets and paying the difference in cash considered usury? Is it permissible to return the necklace and retrieve only the price of the two bracelets without the cash difference paid?

It is impermissible to sell gold for gold or silver for silver except in equal measure and hand-to-hand, meaning that the weight must be equal and the delivery instantaneous. This prohibition is stated in the prophetic traditions because any difference in quantity or price leads to usury (riba).

For example, if there is crafted gold and uncrafted gold, it is not permissible to sell one for the other with a price difference paid for the crafting, as this would be considered usury. Rather, the gold must be sold for its monetary value, and then the other gold purchased with the money.

Scholars have reached a consensus on this ruling and have affirmed that any difference in selling gold for gold or silver for silver, whether by an increase or decrease in weight or price, or by a delay in possession, is considered usury, and the sale is invalidated.

Accordingly, if a person exchanges gold for gold and pays money to compensate for a weight difference, the transaction is usurious and void. The lawful method is to sell the old gold for money, and then buy the new gold with money.

Sellers should be advised to avoid usury and to be made aware of its danger, and to seek what is lawful in all their transactions.