The siliceous remains of microscopic diatoms, which are aquatic plants. Also known as "infusorial earth" and "kieselguhr".

This material is a fossil substance, made up of tiny silicon shells left by trillions of microscopic, one celled algae called diatoms.

Diatoms first appeared 20 million years ago, but flourished in Mesozoic times (ten million years ago) when they lived in such enormous numbers they left vast deposits of their shells up to three thousand feet thick.

Diatoms have one property that sets them apart from other micro organisms. They weave microscopic shells which they use for the protection and locomotion. These shells are covered with a pattern of tiny holes so regular that even the slightest change in their design usually signifies a different species. As some of the ancient specie died, their shells survived, slowly piling up in deposits at the bottom of geological lakes and lagoons. When these lakes dried up, what remained were huge deposits of "diatomaceous earth". Today there are over 1500 uses for diatomaceous earth, from abrasives, filtering agents for water and milk, heat insulators for kilns, to polishing agents in nail polishes and many other applications.

Example of fossilized species

Example of living species