Diatomaceous earth – 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 μm to more than 1 mm, but typically 10 to 200 …
A sample of food grade diatomaceous earth
Diatomaceous earth as viewed under bright field illumination on a light microscope. Diatomaceous earth is made up of the cell walls/shells of single cell diatoms and readily crumbles to a fine powder. Diatom cell walls are made up of biogenic silica; silica synthesised in the diatom cell by the polymerisation of silicic acid. This image of diatomaceous earth particles in water is at a scale of 6.236 pixels/μm, the entire image covers a region of approximately 1.13 by 0.69 mm.
Individual diatom cell walls often maintain their shape even in commercially processed filter media, such as this one for swimming pools