Diatomaceous Earth (DE) and other specialized media, combined in a proprietary formulation. Diatomaceous Earth (DE) is a fossil substance, made up of very small silicon shells left by a type of microscopic, hard-shelled, one-celled algae (trillions of them) called diatoms. It is reported that there are over 1500 uses for DE today, including filtering agents for water and milk, toothpaste abrasive, thermal insulators, organic insecticides, liquid absorbents and more.