Calcined Diatomaceous Earth vs. Non-Calcined: What Is the Difference?

Diatomaceous earth can be calcined or non-calcined. The difference between the two is very important depending on what purpose the DE is being used for.

Calcined diatomaceous earth has been treated at a temperature above 1000ºC. The purpose of this is to further harden the exoskeletons of the diatoms in order to create a better filtering agent. The process causes the amorphous silica that makes up the exoskeleton of the diatom to turn in to crystalline silica. This is a benefit if the diatomaceous earth is to be used as a filtering aid, however crystalline silica can be toxic to humans and animals when inhaled. Calcined diatomaceous earth is not used for animal feed and is not food grade.

Natural diatomaceous earth is non-calcined meaning that it has not been treated at a high temperature. The exoskeletons of the diatoms are still sharp and will provide the suggested benefits. The amorphous silica remains in its natural state and is not considered harmful to animal or human health due to its low crystalline silica content (Red Lake Earth Diatomaceous Earth is less than 1% Crystalline Silica).

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