The comparison of infra red spectra of different kinds of silicas of high specific surface area allowed to draw conclusions about the structure regularity, which appeared to be different for the various kinds of amorphous silicas, such as fine and large pore silica gels, beer stabilizers and white rubber fillers1/. In comparison with the silica gels the fillers of Arsil, Ultrasil and Aerosil type show a more crystallinic nature, which goes together with increased pore volumes and decreased bulk densities. Such feature of the infra red spectrum as the lack of the 960 om−1hydroxyl band was found to be characteristic for Aerosil and enables to distinguish this kind of material from silicic acids precipitated in solution.