Pyrophyllite is a phyllosilicate mineral composed of aluminum silicate hydroxide. It occurs in two more or less distinct varieties, namely, crystalline folia and which compact masses. In the ideal case, the structural formula is expressed by Al2Si4O10(OH)2 for Pyrophyllite is a phyllosilicate mineral composed of aluminum silicate hydroxide. It occurs in two more or less distinct varieties, namely, crystalline folia and which compact masses. In the ideal case, the structural formula is expressed by Al2Si4O10(OH)2 for