Kieselguhr

kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder.It has a particle size ranging from more than 3 mm to less than 1 μm, but typically 10 to 200 μm.

Kieselguhr is used as a filtration aid, mild abrasive in products including metal polishes and 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 coagulation studies, a stabilizing component of dynamite, a thermal insulator, and a soil for potted plants and trees as in the art of bonsai.It is also used in gas chromatography packed columns made with glass or metal as stationary phase.

Kieselguhr consists of the fossilized remains of diatoms, a type of hard-shelled microalgae.

Inhalation of crystalline silica is harmful to the lungs, causing silicosis. Amorphous silica is considered to have low toxicity, but prolonged inhalation causes changes to the lungs.Kieselguhr is mostly amorphous silica but contains some crystalline silica, especially in the saltwater forms.