2. Minerals
This includes gold, silver, lead, brass, carnelian, turquoise, ruby, kohl, salt, tar, oil, sulphur, etc., it is Ehtiyat to consider limestones, different forms of limestones, millstones, and whatever are thought to be beneficial minerals as true minerals. Evidently, the taxability of the latter category will be dealt with according to the rules of normal earnings, not by those of minerals. In the case of minerals it doesn't matter not by those of minerals. In the case of minerals it doesn't matter whether they are found in someone property or a land which is lawful to use.
Rule 4. In the taxability of minerals the standard quantity is a condition. This quantity is equivalent to twenty dinars which is equal to 15 Mithqal of gold currency. This standard quantity applies to all the minerals. It is a necessary Ehtiyat to observe the standard quantity of gold and silver currencies; the exact quantity is taxable, even before the deduction of the expenses and purification of the minerals. If a standard quantity is obtained, Khums will be due on the amount which is left after the deduction of the expenses and purification.
Rule 5. The second condition is that the standard quantity should be obtained at one time. Thus, there is no Khums if it is obtained at several intervals, even if the total amount is the standard quantity. However, after starting to dig for a certain mineral if one changes his mind and starts again, if this will not be considered as obtaining them at different times, the obtained standard quantity will be taxable.
Rule 6. If a group of people join together to obtain certain minerals, if each one's share obtained is a standard quantity, this also is taxable.
Rule 7. The minerals of someone's land belongs to him, provided, they are considered part of his land. Even if someone digs it out without the permission of the owner it will still belong to him (owner) and it will be incumbent on him to pay Khums. If the mineral is obtained from a conquered land which belongs to the Muslims, it will be the property of the one who obtains it, provided, he has done it with the permission of the qualified leader of the Muslims, according to a necessary Ehtiyat. Such minerals will be subject to Khums. Whatever is obtained from a barren land during a conquest will belong to the one who has obtained it and he will have to pay its tax.
Rule 8. If one doubts whether the minerals in his possession amounts to the standard quantity, it is a necessary Ehtiyat to find out.