or conjectured, the currency exchange (sarf) is valid. If he thinks it is not present, the currency exchange is not valid, because its status is that of something non-existent. If he doubts its presence, Ibn Aqil said: It is valid. This is the opinion of some Shafi'is. Al-Qadi said: It is not valid, because its persistence is not known. This is the explicit statement of al-Shafi'i. The reasoning for the first [opinion] is that the default state is its persistence, so it is valid to build upon it in cases of doubt, for doubt does not remove certainty; for this reason, the sale of an absent animal whose life is in doubt is valid; if it then becomes clear that it was dead at the time of the contract, we conclude that the contract was invalid.

Section: It is not permissible to sell the dust of goldsmiths and mines for anything of its own genus, because it is usury-prone property sold for its own genus in a manner where equality between them cannot be known, so it is not valid, like selling a heap [of grain] for a heap. If it is sold for a different genus, Ibn al-Mundhir narrated from Ahmad the dislike of selling mine dust. This is the opinion of Ata, al-Shafi'i, al-Sha'bi, al-Thawri, al-Awza'i, and Ishaq (29), because it is unknown. Ibn Abi Musa said in "al-Irshad": It is permissible. This is the opinion of Malik. It has been narrated from al-Hasan, al-Nakha'i, Rabi'ah, and al-Layth (30). They said: If it is mixed or ambiguous, he should sell it for trade goods (ard), and he should not sell it for coin (ayn) or silver (wariq), because he sold it for what has no usury in it, so it is permissible, just as if he bought a garment for a dinar and a dirham.

718- Issue: He said: (The 'araya [gifts of fruit on trees] which the Messenger of Allah, peace and blessings of Allah be upon him, granted a concession for, is that a person is gifted [the produce of] some palm trees that do not amount to five awsuq, so he sells them based on their estimation [khars] of dates to someone who will eat them as fresh dates [rutab]).

There are five sections in this issue:

The first is regarding the permissibility of selling 'araya in general. This is the opinion of most scholars, including Malik, the people of Medina, al-Awza'i, the people of Syria, al-Shafi'i, Ishaq, and Ibn al-Mundhir.