Is Zakah due on wealth whose acquisition is prohibited if it meets the nisab threshold?
Chapter on Zakat on Gold and Silver
Al-Mughni
Book of Zakat
Primary text
Zakah is due on anything whose possession is prohibited if it reaches the nisab threshold, or if it combines with other holdings to reach the nisab, as previously established. This due Zakah amounts to one-fifth for the recipients of charity, and the remainder is for burial (or interment).
Supporting text
The term 'Rikaz' refers to treasure buried in the earth, derived from the root meaning 'to hide' or 'to stick firmly in the ground.' The foundation for the Zakah of Rikaz is the Hadith narrated by Abu Hurayrah from the Messenger of Allah (peace be upon him): 'The property of a dumb animal causing death is a loss (Jabar), and in Rikaz is one-fifth.' This ruling is unanimously agreed upon, with Ibn al-Mundhir noting no known dissent except that of Al-Hasan, who differentiated between what is found in the land of war (requiring one-fifth) and the land of the Arabs (requiring Zakah).