Diatomaceous earth, commonly referred to as kiesel or gurdiatomite, is a sedimentary rock made from the fossilized remains of single-celled plants. It is soft and can be crushed easily, which yields a white, powdery substance. Although it was first used as an abrasive, diatomaceous earth is now used for several purposes, including cleaning up spills, killing pests, filtering liquids, and growing plants.
Because of the sharp edges on the tiny particles of crushed diatomaceous earth, it has been used as an abrasive for years. Certain metal polishes and toothpastes contain diatomite as an ingredient. As an exfoliant, it has been added to facial scrubs, especially those made specifically for oily skin. Since it is very absorbent, it is believed to absorb excess oil from the skin.
Diatomite particles are able to trap a large amount of liquid, since they are very porous. It is a common ingredient in cat litter, especially since it is considered safe and non-toxic. It is also used to clean up spilled liquid, even toxic or poisonous liquids.
Being abrasive as well as absorbent is one of the reasons that researchers believe that diatomaceous earth make such a good insecticide. The sharp edges can scratch the hard exoskeletons of certain hard to kill pests, including fleas and bed bugs. After the protective outer layer is damaged, the diatomite can then absorb the fluids inside the body of the pest, which causes them to literally shrivel up and die. Many farmers also use food-grade diatomaceous earth to kill intestinal parasites in their animals.
Many people are familiar with diatomaceous earth as a filter for swimming pool and aquarium water. Because it is so spongy and porous, these particles are able to trap large amounts of tiny impurities in water and other liquids. These impurities are caught in the minuscule holes of the diatomite particles and are therefore filtered out. Diatomaceous earth is used to filter drinking water, beer, wine, liquors, and other beverages.
Used as a growing medium, crushed diatomaceous earth has performed quite well. It is fast draining, but it is also able to retain some moisture as well as nutrients. Although it is popular as a bonsai soil, a number of other plants can benefit from diatomite, either added to the soil or as the soil itself.
Diatomaceous earth is also a key component in dynamite. When mixed with diatomite, nitroglycerin becomes much more stable, which makes it easier to work with and transport. Alfred Nobel discovered this use in 1866.