Abstract: Siliceous earth is now widely used as filtering agent in post-processing of gelatin production. Its main function is removing noncollagenous protein and other staining substances from gelatin. The gelatin production practice shows that some siliceous earth samples are of very good filtering capacity, but other samples are not. Four typical siliceous earth samples were collected for the comparison in their filtering capacity. The transmitance electron microscopy (TEM), scanning electron microscopy (SEM), and EDAX were used for the study of their morphology, crystalline state and composition. It was found that the filtering capacity of the siliceous earth is closely related to their morpho logical structure.

Key words: siliceous earth, gelatin, electron microscopy, electron diffraction, morphology