Pyrophllite belongs to clay mineral. It is a layered hydrous aluminum silicate mineral with 2:1 crystal structure. The chemical formula of pyrophyllite is Al2[Si4O10](OH)2. Pyrophyllite belongs to monoclinic system, usually appeared as flaky, radial or dense block aggregate; implicit crystalline dense block is commonly known as “Shoushan stone”, “Lardite”, etc. Pure pyrophyllite is usually white, yellow, light blue or grey. Harness: 1-2; relative density: 2.65-2.90; feels soapy when touching, with excellent insulating property. Pyrophyllite is mainly formed through hydrothermal alteration of acid volcanic rocks or some other metamorphic rocks. It can be used as insulating or refractory materials or used in ceramics, paints, and paper making industries. Dense blocks can be also used for engraving.