Diatomaceous Earth comes from an extremely pure fresh water deposit of the diatom Aulacoseira from a deposit created in the Miocene epoch. Why is this diatom so special? Its shell is made of amorphous silica. Its shape and hardness are important to how it works, the hardness keeps it from dissolving in liquid and the holes along the diatom's wall allow it to absorb moisture, hence its use as an anti-caking agent. Mixing Rate: As an anti-caking agent to be mixed in animal feeds in an amount not to exceed 2% by weight of total ration.