Is it permissible to sell a portion of a bulk quantity of grain known by visual inspection?
Chapter on Selling Assets and Fruits
Al-Mughni
Book of Sales
Primary text
It is permissible to sell half, a third, or a known fraction of the bulk quantity. This is because what is permissible in bulk is also permissible in part, similar to livestock. Since the whole is known by sight, its part is likewise known.
Supporting text
Ibn Aqil stipulated that this is only valid if the bulk quantity has uniform parts. If it is varied, such as the bulk grain held by a village grocer, it is not valid. However, another view suggests it is valid because the buyer purchases a common share and is entitled to the good and bad portions proportionally.