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Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite.
A 1736 (OTTO) Aluminium hydroxide, 76.5% Cas 21645-51-2 - used as a Claus catalyst support for waterproof fabrics.