Diatomaceous earth (Kiselgur)

 White sedimentary rocks, with a very porous and therefore light structure, are extracted. Are formed by the accumulation of siliceous shells of algae in fossil state. Have been used for years as filtration assitants in polishing processes in the manufacture of edible oils, wines, alcohols, pharmaceuticals products, etc. due to the excellent properties of adsorption of the kieselgur.