Diatomaceous earth ( /ˌdaɪ.ətəˌmeɪʃəs ˈɜrθ/) also known as D.E., diatomite, or kieselgur/kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 3 micrometre to more than 1 millimeter, but typically 10 to 200 micrometres. This powder has an abrasive feel, similar to pumice powder, and is very light as a result of its high porosity. The typical chemical composition of oven-dried diatomaceous earth is 80 to 90% silica, with 2 to 4% alumina (attributed mostly to clay minerals) and 0.5 to 2% iron oxide.
Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae. It is used as a filtration aid, mild abrasive in products including toothpaste, mechanical insecticide, absorbent for liquids, matting agent for coatings, reinforcing filler in plastics and rubber, anti-block in plastic films, porous support for chemical catalysts, cat litter, activator in blood clotting studies, and a stabilizing component of dynamite. As it is heat-resistant, it can also be used as a thermal insulator.
Read more about Diatomaceous Earth: Specific Varieties, Climatologic Importance, Safety Considerations, The Age and Shape of Diatoms
Famous quotes containing the word earth:
“For you are a people holy to the LORD your God; the LORD your God has chosen you out of all the peoples on earth to be his people, his treasured possession. It was not because you were more numerous than any other people that the LORD set his heart on you and chose you -for you were the fewest of all peoples.”
—Bible: Hebrew, Deuteronomy 7:6,7.