Machinable glass-ceramic has found extensive applications in dentistry, aerospace, and vacuum industries. In the present study, glasses were first prepared in the SiO2–Al2O3–MgO–F system. Glass-ceramics with mica-based crystals were then prepared by heat treatment nucleation and growth. To eliminate the interfering phases and improve the machinability, the glass-ceramic was crushed by mechanical milling, followed by spark plasma sintering (SPS) at 750 ◦C and a pressure of 30 MPa. The microstructure of the samples was also explored by SEM. The major phase in the initial glass-ceramic was fluorophlogopite. Regarding uniaxial pressure in the SPS process, signs of the preferred crystal orientation were found in the images of SPS samples. The hardness of the SPS sample was 553 H V which was lower than that of the initial glass-ceramic (811 HV). Machinability was improved due to the increase in the content of the mica phase and its preferred orientation.
