Diatoms are single-celled algae of the phylum Bacillariophyta and are found in all the Earth's oceans. One of the most prolific sea organisms, the nearly 16,000 species of this group form a significant portion of the aquatic food chain.

Diatom cell walls are composed of silica fashioned into a myriad of beautiful geometrical shapes and patterns. Diatomaceous earth, a substance composed of fossil diatoms, is used for making filters, insulation, abrasives, paints, and varnishes.