Diatomite is a naturally occurring biogenic siliceous sedimentary rock, mainly composed of silicified fossil remains of ancient single-celled aquatic plants (diatoms). Its unique porous discoid or sieve-like microstructure endows it with excellent properties including low density, high porosity, large specific surface area, strong adsorbability, chemical inertness, high temperature resistance and non-toxicity. It usually appears as a fine, loose powder in white, off-white or light yellow color.