Who owns a mineral that is discovered in land that was previously granted?
Chapter on Selling Assets and Fruits
Al-Mughni
Book of Sales
Primary text
It is related that the descendants of Bilal ibn al-Harith sold land to Umar ibn Abd al-Aziz. When a mineral was discovered, they claimed they only sold the land, not the mineral. Umar ibn Abd al-Aziz accepted the Prophet's grant document (qati'ah) given to Bilal, kissed it, and returned the mineral to them.
Supporting text
It is related from Abu Talib, citing Ahmad, that if the mineral appears within a person's established ownership, they own it. The apparent meaning of this view is that the right is not given to the seller (from the previous transaction), nor is the option granted to them, because the mineral is considered a part of the land, like stones within it that possess significant value.