Vermiculite is a hydrous phyllosilicate, natural, inorganic and non-toxic mineral, under the action of high temperature will expanded 7-10 times from its original size. Exfoliation occurs when the mineral is heated sufficiently.

Formula: (Mg,Fe2+,Fe3+)3[(Al,Si)4O10](OH)2·4H2O

It is a relatively rare mineral that belongs to silicate. Its crystal structure is a single oblique crystal system, from its shape looks very much like mica. Vermiculite is produced by a certain amount of granite hydration. It is generally produced at the same time as asbestos. Because Vermiculite has the ability of ion exchange, it has a great effect on the nutrition of soil. The world’s total vermiculite production in 2000 exceeded 500,000 tons. The leading producers are China, South Africa, Australia, Zimbabwe and the United States.