How is the value of a gold necklace calculated when it is returned? Is it based on its current value or on the weight of the gold that was sold previously?

If you borrow gold jewelry, you must return an equivalent amount in weight and quality. The difference in its value is not considered. However, if you both agree to repay the debt in cash, it must be at the price of gold on the day of repayment, not on the day of borrowing. For the borrower, if they borrowed gold, they return gold; and if they borrowed the price of gold (i.e., cash), they return cash.