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Related to Palagonite: Palagonite tuff
a glassy mineral substance of yellow-brown, brownish green, or dark brown color, having a high water content and sometimes occurring in partially devitrified form. It is found in basalts and in diorites and their tuffs. Palagonite contains 13 to 23 percent water, 37 to 40 percent silica, and 12 to 21 percent iron oxides. The most common form of palagonite is found near the city of Palagonia (hence the name) in Sicily and also in Iceland, Franz Josef Land, the Bol’shezemel’skaia Tundra, and the Timan Ridge.