Terms of the Trade: Diatomaceous Earth

Diatomaceous earth is a soft rock or powder consisting of the fossilized remains of diatoms, a category of hard shelled microalgae. Trillions of different kinds of diatoms live all over Earth, mostly in water, producing about 20% of the planet's oxygen, mostly through photosynthesis.

Unprocessed diatomaceous earth makes an excellent natural insecticide and pest repellent. The tiny jagged edges of its particles won't hurt humans or pets, but they can kill tiny creatures like fleas, maggots, and silverfish.

Processed diatom fossils are used as an element in many otherwise unrelated products, including fertilizers, blood clotting agents, cat litter, dynamite, and toothpaste.