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PHYCOLOGICAL SOCIETY OF AMERICA
Diatoms in Industry
Because of the heavy silica in diatom cell walls, dead cells tend to sink to the ocean floor, forming large deposits of diatomaceous earth that may be collected for industrial or paleontological uses. In a strict sense, diatomaceous earth should be considered fossil fuel, because it is made up literally of millions of tiny preserved skeletons!
Areolae are the secret to the success of old diatom tests in most of their industrial uses. This fine structure traps particles in fluids when used as a filter, or traps an insulating layer of air in more terrestrial uses.
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As a filter:
syrups, alcoholic and nonalcoholic drinks, medicines, solvents and chemicals.
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As a filler:
paper, paint , ceramics, and detergent.
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As Insulation:
high-temperature insulation, including fire doors; sound insulation.
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As a Mild Abrasive:
the oldest use of diatomaceous earth. Metal polish and toothpaste. I can't find a toothpaste that is using diatomaceous earth any more; Tom's of Maine is switched to calcium carbonate.
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For Optical Image Quality:
another very old use of diatoms. Because of a regular, gridlike patterning of areolae in some species, diatoms may be used to measure the resolving power and contrast of light microscopes.
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copyright John Becker 1996.