The formation of crystal nuclei occurs when alkaline aluminosilicate gels are treated at temperatures below the crystallization temperature or during crystallization of gels rather than during precipitation of the gels. The linear growth rate of the crystals of Na-A zeolites yielded by alkaline aluminosilicate gels in the presence of amorphous seeds is a function of the product of the concentrations of the silicate and aluminate ions in the intermicellar liquid.