They are extracted of white sedimentary rocks, of very porous structure and therefore light. They are formed by the accumulation of siliceous shells of algae in the fossil state. They have been used for years as filter auxiliaries in polishing processes in the manufacture of edible oils, wines, alcohols, pharmaceutical products, etc.
due to its excellent absorption properties. In the filtration of laboratory samples we found its usefulness in combination with a filter paper with a smaller pore size than the measurement of the size of kieselguhr particles (see table). It can even be used together with FILTER-LAB diatom filter paper ref. 1297. This auxiliary is especially interesting in the filtration of difficult samples with particles of colloidal size.