Diatomaceous earth (de) is the remains of microscopic one-celled plants (phytoplankton) called diatoms that lived in the oceans & lakes that once covered The Western part of the US & other parts of the world. Diatoms (algae) are the grass of the oceans & lakes. Just as grass is the staple food of earth animals, diatoms are the food of the ocean or fresh water grazers. Magnified 7000 times, Diatomaceous earth looks like spiny honeycombs. Diatomaceous earth is mined from underwater beds or from ancient dried lake bottoms thousands of years old. This means, Diatomaceous earth has an unlimited shelf life Provided you keep it dry. Diatomaceous earth is mined, milled, & processed into a myriad of types For a large variety of uses. Filtering & Filler are two main uses but Diatomaceous earth also ends up in paints, cosmetics, drugs, etc. Because the milling produces different sized & shaped particles, It is important NOT to use the filtering type for agricultural purposes. Our Diatomaceous earth is organic OMRI listed food chemical Codex grade. It is a non-treated, non-calcined fresh water Diatomaceous earth. It comes from fresh water lake beds & is mined, crushed, sifted, bagged, pure White in color & contains less than . 5% crystalline silica. There are food grade Diatomaceous earth products that are yellow or Tan in color which indicates higher iron content. Those which are gray in color contain more clay. As an anti-caking agent for animal feed de is FDA approved: for internal & external use & has a rating of food chemical Codex grade