Their composition will vary according to the area they lived and died in. Most DE contain silicon, sodium, aluminum, manganese, boron, magnesium, iron, calcium, and copper. Also Fresh water DE deposits contain lower percentages of silica than does salt water deposits. Amorphous DE is very different from crystalline silica where health is concerned. This is why pool grade DE is not safe to use on your garden or farm.
Many companies add an acid to complicate matters.
This slowly dehydrates the insect. The DE effects the insect from the outside as well as from the inside if the insect eats the DE as well. DE can be fed to your dogs, cats, horses without any harmful effects to them. It is a natural dewormer while providing trace minerals. One cup per daily ration for your horses.