Diatomaceous earth, also known as diatomite, kieselguhr, kieselgur, and Celite, is a naturally occurring, soft, chalk-like, sedimentary rock mineral that is easily crumbled into a fine white to off-white powder. This powder has an abrasive feeling similar to pumice powder and is very light-weight due to its high porosity. It is made primarily of silica and consists of fossilized remains of diatoms, a type of hard-shelled algae.
Diatomaceous earth is also used as an insecticide due to its abrasive properties. The fine powder causes small cuts in the waxy outer layer of insects, causing them to dehydrate.
There are 2 different kinds, cleaner grade and food grade. It is commonly sold in hardware and garden stores as an “organic pesticide” and is available from a number of storage food dealers. (People use it to prevent bugs in their grains.)