Zeolites are among the least-known products for environmental pollution control, separation science and technology. The work studies synthesis of gel aging and duration of Na-X zeolite crystallization in studied conditions. To obtain the maximum crystallinity (40%) zeolite, gel aged for 24 h at room temperature and it lead to reduction of zeolite synthesis’ (95 °C) duration from 3 to 0.5 hours. The longer duration of aging time had been, the smaller zeolite crystals were obtained. An obtained IR spectrum showed that all samples of the absorption bands at the positions of maximum were as follows: 983-1012 cm-1, 717-756 cm-1, 564-590 cm-1 and 450-465 cm-1 were practically identical. This allowed ascribing tested samples to one type of zeolites Na-X. An obtained DSC curves for all samples were practically similar and have a wide endothermic peak with maximum 135 – 169 oC and a small exothermic peak about 853 – 956oC. Thermal analysis like IR spectra allowed ascribing the tested samples to one type of zeolites Na-X. The zeolite gel aging can be effectively used not only for shortening the duration of hydrothermal crystallization, but also for controlling size of zeolite crystals