What is the ruling on exchanging gold for gold by paying the difference in weight, not value, without considering fineness or quality?

It is permissible to sell gold for gold, weight for weight, hand to hand. Scholars differed on the ruling concerning selling gold for gold with the payment of an excess amount:

The Majority (Malik, Ash-Shafi'i, and Ahmad): Prohibited this, fearing falling into usury (riba). They hold that the solution is to sell the gold for currency, then purchase the other gold with that currency. Some Scholars (Abu Hanifa and one narration from Ahmad): Permitted this, provided there is no trickery intended to facilitate usury.

The view of the majority is more cautious for a Muslim to avoid doubtful matters.