•HRTEM images revealed that the size of the nanoparticles are 100 nm and smaller.•Nanocrystalline Al2SiO5 particles can be partially amorphized under temperature.•The “triple point” in the DTA spectra is observed at 850 K.•At the cooling process the evaluated And – Sil transition stopped in small quantities. DTA, TGA, and DTG methods were applied at different heating rates to comparative study of thermal parameters of nanocrystalline Al2SiO5particles. Hydroxyl groups on the surface of the nanoparticles and the process of their release under the influence of temperature were explained by the corresponding DSC spectra. Simultaneously, the size and composition of the nanoparticles were measured by HRTEM imaging and EDX analysis. Possible andalusite − sillimanitetransitionofAl2SiO5modifications, andamorphization processes under the influence of temperaturewere investigated by the DTA approach. Around 850 K “triple point” of Al2SiO5modifications was analyzed by the DSC spectroscopy.