What is the ruling of Islamic law regarding the condition of repaying a loan with the equivalent value of gold at the time of repayment? And is that considered usury (riba)?

It is not permissible when concluding a loan contract to agree to repay it with its value in gold or another currency, because this contains the meaning of usury of delay (riba an-nasi'a); it is a deferred exchange. The resolution of the Islamic Fiqh Academy has stipulated that it is not permissible to agree to record the debt in what equals the value of the currency in gold or another currency, whereby the debtor is obligated to repay the debt in gold or the other agreed-upon currency.