PALYGORSKITE (Paligorskite) (Mg,Al)2 Si4 O10(OH) ·4(H2O) Palygorskite is named after a deposit in the Ural Mountains, Russia. The Dana's System of Mineralogy spells it Paligorskite, but since the origin is Russia, and the Russians named it, the Russian spelling would be correct. It is a magnesium, aluminum silicate mineral, and it is fibrous, if broken apart. In some local areas it is known as "Mountain Leather", because it has the feel of leather, and it is very light, despite having a SG of 2.5. It is monoclinic, has good cleavage, is relatively soft (2), is white to grayish, yellowish or gray-green. "It occurs as a alteration product of magnesium silicates in soils and sediments; in lacustrine marls, carbonate rocks and mafic igneous rocks, in clay gouge associated with fault movement"** It is typically associated with calcite, dolomite, talc, chlorite, quartz, opal and montomorillonite. Palygorskite occurs over a wide area, including Asia, North America, Europe and Africa. It has been studied as a substitute for asbestos, but I know of no commercial uses. However, it can be a part of many clays, including bentonite and montomorillonite, which are used widely in many industries. ** Dana's System of Mineralogy (6th Edition)