Is the increase in the price of gold the right of its original owner or mine, knowing that I intended to buy it but have not yet sold it?

Scholars have differed on the validity of an agent purchasing for himself what he was appointed to sell. Those who permitted it stipulated the principal's permission. Based on all opinions, the increase in the price of gold jewelry belongs to the owner, and the agent has no right to it because it has not entered his possession. If the agent wishes to purchase it for himself, he must inform the owner of its current price and his desire to buy it at that price. If the owner accepts, it is permissible; otherwise, it is not.