Ruling on selling old gold for new gold

Question:
I can say that many gold sellers, and the women who buy gold, fall into riba (usury or interest). This is like exchanging, meaning gold for gold, and when the shop owner is left with some money, he agrees to wait for the person based on the familiarity between them. We have asked many women about this exchange, and they say: Yes, we exchange constantly, and we know nothing about riba (usury or interest)?

Answer:
Sins occur; it is not said that they do not occur. Sins occur among people, they occur in riba (usury or interest), they occur in sins other than riba (usury or interest), all of them occur. But the important thing is the treatment of these sins through the prescribed limits, sermons, reminders, and advice. Otherwise, sins occur. So riba (usury or interest) occurs from women, and from men with the goldsmiths, and with those other than goldsmiths. It is not permissible to remain silent about them. Whoever knows that a sin occurs from him should advise and direct him to good.
So the one who buys from the goldsmiths necklaces, or bracelets, or other things, must buy them with money hand-to-hand, in the case of bracelets, in the case of necklaces, in... [then] he buys them with currency hand-to-hand, or with a type other than currency. He buys, for example, a necklace of gold, or of silver, or a ring of gold, or a bracelet of gold, or other things. He buys them with other than currency. He buys them, for example, with food, he buys them with clothes, he buys them with cardamom, with coffee, with sugar for a term. There is no harm. But with currency, no, it must be hand-to-hand. With gold, it must be hand-to-hand.
So if he sells; he gives the used rings, or the used things, for something new, it must be hand-to-hand, for example, like for like. Otherwise, let her buy the new one with a separate price, and let her sell the old one for a separate price. As for giving this for this and an increase, it is not permissible. This is riba (usury or interest). Selling this new one for this old one, and an increase of one or two pounds, it is not permissible. So it is necessary to buy the new one with a separate price, hand-to-hand if it is from currency, from paper. And if it is with other than currency... for a term, food for a term, clothes for a term, there is no harm, meaning it is not ribawi (involving usury) if he sells gold for cardamom, or coffee, or clothes, or another raw material, or other goods other than currency; then there is no harm for a known term. But with currency, no, it must be hand-to-hand. If it is gold for gold, it must be like for like, exactly the same, face to face, hand-to-hand, they do not separate. And so it is with silver.
If he sells silver for gold, there is no harm, but hand-to-hand. If he buys from the goldsmith a bracelet of gold with paper hand-to-hand; then there is no harm. But if he says: Go, and then come back to me, that is not correct. It must be hand-to-hand. And if the woman and the man do it, he is advised, and it is made clear to him that this is what is wrong. And the Hisbah (public authority) and the Hisbah (public authority) must carry out this matter, and disapprove of the one who did this thing. And whoever does not desist; he is punished with discipline, imprisonment, and beating if he does not refrain from what Allah has forbidden him.