Kieselguhr

Kieselguhr, known in English as diatomaceous earth, is a soft, crumbly sedimentary rock composed primarily of the fossilized silica shells of diatoms. The material is largely amorphous silica with variable amounts of water and minor impurities, giving it a high porosity and large surface area.

Formation and structure arise from the accumulation and lithification of diatom frustules in aquatic environments. The microscopic silica scales create a porous, low-density material with a fine, web-like structure that makes Kieselguhr an effective filtration medium and an abrasive additive in various applications.

The name Kieselguhr derives from German, with Kiesel meaning “stone” or “flint” and guhr an old term for diatomaceous earth. Deposits occur worldwide, with historic and ongoing mining in Europe and extensive production in North America and other regions.

Primary uses center on filtration and purification. As a filtration aid, Kieselguhr clarifies liquids such as beer, wine, and fruit juices by trapping suspended particles while allowing liquids to pass through. It is also employed as a mild abrasive, filler, and absorbent in cosmetics, polishes, and paints. Finely milled, food-grade diatomaceous earth is used as a mechanical insecticide and as a soil amendment in some gardening or agricultural contexts.

Safety considerations focus on dust exposure. Inhalation of diatomaceous earth dust can irritate the respiratory tract, and products may contain varying amounts of crystalline silica depending on processing. Proper dust control and handling practices are recommended, and food-grade or consumer-grade products are typically marketed with specific usage guidelines.