Grandpa's Diatomaceous Earth is fossilized Diatoms, a type of microscopic algae. Diatoms live for about a week before settling on the lake bed, where they become a siliceous sedimentary rock. It's appearance is pure white and very fine, almost powdery but when touched it is very drying. Some DE has a darker coloring but not Grandpa's Diatomaceous Earth it's always brilliantly white. Freshwater food grade Diatomaceous Earth is all natural and contains NO pesticides or Chemicals. People are using DE to do more and more everyday as an alternative to using manufactured chemicals.