Vermiculite is a kind of natural, non-toxic, inorganic silicate mineral, whose raw ore looks like mica. Vermiculite is formed by the hydrothermal alteration or weathering of minerals, usually biotite and phlogopite. When heated,it expands like leech. Vermiculite are divided into raw vermiculite and expanded vermiculite by stages, and according to the color, it can be divided into golden vermiculite, silvery white vermiculite, milky white vermiculite.