Is it permissible to purchase usurious items by description without seeing them, with mutual possession in the contract session, such as buying described gold and silver and receiving them later in the same session after paying the price?

For the validity of selling usurious items like gold and silver, immediate possession (al-taqabud) in the contract session is a prerequisite. This is not possible if the item being sold is absent, unless the room where the item is located is close to the shop such that going to it is not considered a dissolution of the contract session. However, if going to it constitutes a separation, then it is not permissible. But, if the going is for the purpose of estimating the price and preparing the commodity, and then the contract is concluded with offer and acceptance after the seller returns and delivers the item, there is no issue with that. As for non-usurious items, selling an absent one is valid by description without visual inspection, even if it is absent from the contract session, and it is not required that seeing it involves hardship.