Abstract <p>The patterns of formation of geopolymer materials based on aluminosilicates of the kaolinite subgroup (Al₂Si₂O₅(OH)₄·<i>n</i>H₂O) with different particle morphologies using natural platy kaolinite and nanotubular halloysite as an example under conditions of their alkaline activation are studied. It is found that the compressive strength of halloysite-based samples can be 1.4 times higher than the strength of kaolinite-based samples and reach 85 MPa. X-ray diffraction and electron microscopy studies show differences in the phase composition and morphology of the resulting samples depending on the nature of the initial precursor. Nanotube halloysite-based samples geopolymerize over a wide range of SiO₂/Al₂O₃ ratios, which leads to enhanced mechanical strength. Platy kaolinite can recrystallize under alkaline activation conditions into zeolites with A and Y structures, which, accordingly, reduces the mechanical strength of the samples.</p>