What is the ruling on working for a jewelry company that buys and sells gold bullion and coins, where a percentage of the manufacturing cost is deducted when repurchasing from the customer, and then it is resold without being melted down?

For the sale of gold for currency to be valid, immediate possession must take place in the same session. If gold is exchanged for gold, then immediate possession and equality in weight are required, based on the Prophet's (peace be upon him) saying: "Gold for gold... like for like, equal for equal, hand to hand." Monetary currencies are subject to the same rulings as gold and silver.

There is no harm if the buyer sells the gold he possesses to the same seller at a mutually agreed-upon price, provided that this was not a condition in the initial sale or pre-arranged. However, it is impermissible for the buyer to leave the gold with the seller because it is a stratagem for exchanging currency for currency, and this is prohibited usury (riba). Similarly, if the second sale is stipulated within the first sale, this is forbidden because it involves stipulating one contract within another, which leads to usury.