Diatomite

Diatomite, also called diatomaceous earth, is a white or cream-colored, crumbly, porous rock. It is made of the fossil remains of diatoms, which are single-celled water plants with silica (a white or colorless crystalline compound) cell walls. Diatom fossils build up on the ocean bottoms to form diatomite. In some places, where the oceans have receded over time, diatomaceous earth exists as dry land.

Diatomite is chemically unreactive and has a rough texture and other unusual physical properties that make it suitable for many scientific and industrial purposes. Among the uses of diatomite are: filtering agent; building material; heat, cold, and sound insulator; catalyst carrier; filler absorbent; abrasive; and ingredient in medicines. By soaking diatomite in liquid explosive nitroglycerin, one can produce dynamite.