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 1 micrometre to more than 1 millimeter, but typically 10 to 200 micrometres. This powder has an abrasive feel, similar to pumice powder, and is very light as a result of its high porosity. The typical chemical composition of oven-dried diatomaceous earth is 80 to 90% silica, with 2 to 4% alumina (attributed mostly to clay minerals) and 0.5 to 2% iron oxide.

Kieselgur (femininum) (auch Bergmehl, Diatomeenerde, Diatomeenpelit, Diatomit, Infusorienerde, Kieselmehl, Novaculit, Tripel, Tripolit, Celit) ist eine weißliche, pulverförmige Substanz, die hauptsächlich aus den Siliciumdioxidschalen fossiler Kieselalgen (Diatomeen) besteht.

Les Kieselguhrs ou terre d'infusoires sont des micro-fossiles : les diatomées, micro-algues marines qui sécrètent un squelette siliceux.

Kiselgur är en gråvit mjölliknande jordart, som består huvudsakligen av kiseldioxid. Den har bildats genom sedimentering av kiselalger.

Ziemia okrzemkowa (ziemia diatomowa, diatomit) –  skały organogeniczne utworzone głównie z pancerzyków glonów jednokomórkowych - okrzemek.