Diatoms and desmids are grouped under chrysophytes of kingdom monera. They live in fresh water as well as in marine environment. Diatoms are microscopic, unicellular organisms of various colours and diverse forms. They may be circular, rectangular, triangular, elongated, spindle shaped, half moon shaped  and filamentous. Their cellwall is chiefly composed of cellulose impregnated with glass like silica. It shows sculpture and ornamentations.

Diatoms have left behind large amount of cellwalls deposits in their habitats. This accumulation over billions of years is referred to as diatomaceous earth or diatomite. Which is mined and used in various industries. The material obtained from diatomaceous earth is used in polishing and Alteration purposes of different products.