Vermiculite Soil has a mica-like structure, in fact, is also very easy to break, will expand after absorbing water, characteristics, water retention, very water retention. It is a hydrous phyllosilicate mineral that undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently, and commercial furnaces can routinely produce this effect. Vermiculite forms by the weathering or hydrothermal alteration of biotite or phlogopite. The comprehensive character is slightly better than perlite, which can be used to regulate soil moisture. Each peddler quality is uneven, the difference is very big, the individual feels the color is lighter the better the harder, that kind of brown broke open at a moment.