Diatomaceous earth is obtained from Bacillariophyceae. Diatomaceous earth is a naturally occurring, soft, siliceous sedimentary rock and contains particle size ranging from less than 3 μm to more than 1 mm in range. Diatoms are a class of unicellular algae Bacillariophyceae, usually occurring singly and sometimes colonial or filamentous and generate about 50 percent of the oxygen produced on the planet each year. A diatom is surrounded by a cell wall called a frustule and made of silica mostly hydrated silicon dioxide. The diatomaceous earth is obtained from the accumulation of these cell walls of diatoms that composed of hydrated silicon dioxide.