Why Food Grade Diatomaceous Earth: To find out why, spend a day in our office answering phone calls and emails. You will hear some heart breaking stories. The most rewarding conversations are the ones where DE has been a solution that finally worked. Diatomaceous Earth packaged under the Lumino label comes from an extremely pure fresh water deposit. It is almost pure white and consists of at least 85 percent Silicon Dioxide. Darker colored Diatomaceous Earth often contains an excess of other minerals such as iron, or a high percentage of clay.