Bukhari

Narrated Abu Huraira: Allah's Apostle said, "There is no compensation for one killed or wounded by an animal or by falling in a well, or because of working in mines; but Khumus is compulsory on Rikaz."

And Imam Malik (may Allah have mercy on him) and Imam Shafi’i (may Allah have mercy on him) said: Rikaz is the treasure from the time of ignorance (pre-Islamic era). Whether the amount found is little or much, one-fifth is to be taken from it. And a mine is not rikaz. And the Prophet (peace and blessings of Allah be upon him) said regarding mines: If someone falls into it or dies while working in it, then his life is lost in vain. And in rikaz, one-fifth is due. And Caliph Umar bin Abdul Aziz used to take one-fortieth from mines: five out of two hundred coins. And Imam Hasan al-Basri (may Allah have mercy on him) said: Whoever finds rikaz in the land of war, one-fifth is to be taken from it, and if it is found in a land of peace and treaty, then zakat, one-fortieth, is to be taken from it. And if something is found in the land of the enemy, it should be returned (perhaps it is the property of a Muslim); if it is the property of the enemy, then one-fifth is to be paid from it. And some people said: A mine is also rikaz, like the buried treasure of the time of ignorance, because the Arabs say «أركز المعدن» when something comes out of it. Their answer is: If something is gifted to a person, or he earns profit, or his garden yields much fruit, they say «أركزت» (even though these things are, by consensus, not rikaz). Then these people contradicted their own statement. They say: Hiding rikaz is not bad, and one-fifth need not be given.

And Imam Malik (may Allah have mercy on him) and Imam Shafi’i (may Allah have mercy on him) said: Rikaz is the treasure from the time of ignorance (pre-Islamic era). Whether the amount found is little or much, one-fifth is to be taken from it. And a mine is not rikaz. And the Prophet (peace and blessings of Allah be upon him) said regarding mines: If someone falls into it or dies while working in it, then his life is lost in vain. And in rikaz, one-fifth is due. And Caliph Umar bin Abdul Aziz used to take one-fortieth from mines: five out of two hundred coins. And Imam Hasan al-Basri (may Allah have mercy on him) said: Whoever finds rikaz in the land of war, one-fifth is to be taken from it, and if it is found in a land of peace and treaty, then zakat, one-fortieth, is to be taken from it. And if something is found in the land of the enemy, it should be returned (perhaps it is the property of a Muslim); if it is the property of the enemy, then one-fifth is to be paid from it. And some people said: A mine is also rikaz, like the buried treasure of the time of ignorance, because the Arabs say «أركز المعدن» when something comes out of it. Their answer is: If something is gifted to a person, or he earns profit, or his garden yields much fruit, they say «أركزت» (even though these things are, by consensus, not rikaz). Then these people contradicted their own statement. They say: Hiding rikaz is not bad, and one-fifth need not be given.

Narrated Abu Huraira: Allah's Apostle said, "There is no compensation for one killed or wounded by an animal or by falling in a well, or because of working in mines; but Khumus is compulsory on Rikaz."