Frustule

The frustule is composed almost purely of silica, made from silicic acid, and is coated with a layer of organic substance, which was referred to in the early literature on diatoms as pectin, a fiber most commonly found in cell walls of plants.

The frustule also contains many pores called areolae and slits that provide the diatom access to the external environment for processes such as waste removal and mucilage secretion.

[8] When diatoms die and their organic material decomposes, the frustules sink to the bottom of the aquatic environment.

[9] There is also research underway regarding the use of diatom frustules and their properties for the field of optics, along with other cells, such as those in butterfly scales.

[2] As the diatom prepares to separate it undergoes several processes in order to start the production of either a new hypotheca or new epitheca.