Transparent glass-ceramics are attracting more and more attention as a material for protecting the screens of electronic devices. The paper considers the possibility of carrying out ion-exchange of transparent gahnite glass-ceramics containing a small Na2O content. The structure and properties of glass-ceramics before and after ion-exchange were studied by x-ray diffraction analysis, transmission electron microscopy, Raman spectroscopy, laser-induced breakdown spectroscopy, and Vickers hardness determination. It is shown that, under certain conditions, ion-strengthening of glass ceramics with a low content of alkali ions can lead to an increase in microhardness values.