There are many deposits of diatomaceous earth in the world, but only some of them are both pure enough and large enough to serve as a source of raw material for the production of Diatomaceous earth filters and filter aids.
The Amazing Diatom
Diatoms are unicellular plants of microscopic size. There are many varieties that live in both freshwater lakes and saltwater oceans, staying close to the surface where they form part of the abundant plankton. Alive, they are at the base ofthe food chain. Dead, they leave a tiny skeleton known as a frustule, often of great beauty and intricacy like microscopic jewels.
Whereas most other plants use solar energy to synthesize cellulose for their cell walls, the diatom has elected to extract amorphous silica from the water, building for itself what amounts to an elegant, but strong shell with highly symmetrical perforations.