Abstract <p>The influence of hydrothermal synthesis conditions on the porous textural characteristics and morphology of saponite NaMg₃[AlSi₃O₁₀](OH)₂·<i>n</i>H₂O is studied. Saponite is synthesized by hydrothermal crystallization from a gel of the corresponding composition in the temperature range from 200 to 350°C, the duration of synthesis ranges from 2 to 12 days, at a pressure of 700 atm. The obtained samples are studied using X-ray diffraction, low-temperature nitrogen adsorption, and scanning electron microscopy. It is established that varying the synthesis conditions makes it possible to obtain saponite with different degrees of crystallinity and porosity. The morphology of the particles is also determined by the synthesis conditions and can be spongy or lamellar. The possibility of forming a spongy structure using saponite is demonstrated for the first time. The specific surface area can vary in the range from 170 to 690 m²/g.</p>