What is the ruling on selling gold containing zircon stones at the price of gold, with the buyer's knowledge of that?

Selling gold that contains zircon stones at the price of gold is permissible if sold for silver or paper currency, provided that it is visible to the eye and the buyer is aware of it. However, if it is sold for gold, the stones must be separated to determine the weight of the pure gold to ensure equality. This is based on what Muslim narrated from Faddalah ibn Ubayd regarding the sale of a necklace, where the Prophet, peace and blessings be upon him, ordered the gold to be removed from the necklace and said: "Gold for gold, weight for weight," and "It should not be sold until it is separated." This is the view adopted by Al-Shafi'i and Ahmad. Sheikh Ibn Uthaymin issued a fatwa prohibiting the sale of gold with settings for gold of the same weight due to its involvement in riba (usury).