The structure of leached products from mechanically amorphized kaolinite was investigated by various techniques. The Si-29 MAS NMR spectrum of the leached products showed peaks at - 102 and - 111 ppm, assigned to the silanol groups and the three-dimensional silica framework, respectively. The micropore size distribution calculated by the Horvath-Kawazoe method, using Ar gas as the adsorbate, showed a maximum at 0.9 nm, suggesting slit-shaped pores formed between the layers of the mechanically destroyed kaolinite. Longer leaching times reduce the number of micropores due to a condensation reaction.