<p>Transparent glass-ceramics containing MgSiO₃ and/or Mg₂SiO₄ nanocrystals were prepared. Effects of MgO/SiO₂ ratio on crystallization properties of MgSiO₃ and Mg₂SiO₄ nanocrystals were investigated. When the MgO/SiO₂ ratio is relatively low, crystallization of MgSiO₃ is favored, whereas a higher MgO/SiO₂ ratio tends to promote the crystallization of Mg₂SiO₄. Glass-ceramics are transparent in the visible range due to the small size of the precipitated nanocrystals. Replacing SiO₂ with MgO results in an increase in Vickers hardness, and the Vickers hardness can be further enhanced through the precipitation of MgSiO₃ and Mg₂SiO₄ nanocrystals. The findings presented herein are meaningful for the preparation of highly transparent glass-ceramics containing MgSiO₃ and Mg₂SiO₄ nanocrystals.</p>