Does Zakat apply to all excavated materials, irrespective of type?
Chapter on Zakat on Gold and Silver
Al-Mughni
Book of Zakat
Primary text
Zakat is obligatory on all extracted substances possessing value, provided they are extracted as minerals. The evidence for this general application rests upon the Quranic verse concerning what is brought forth from the earth (Quran 2:267) and the principle that any gain from such material mandates Khums, equating the extraction to the obligation of Zakat.
Supporting text
Malik and Al-Shafi'i hold that Zakat is only due on gold and silver, citing the Hadith, "There is no Zakat in stone," and arguing that other excavated wealth resembles red clay, which is not subject to Zakat.