In this research study, magnesium fluoride nanoparticles were successfully produced by the fluorination and carbonation method. MgF2 nanoparticles were calcined at temperature of 100, 300, 400, 500, 600, 640, and 680 °C. Also, polycrystalline magnesium fluoride ceramics were prepared using a hot-pressing process from calcined powders. The optical, structural, and mechanical characteristics of the magnesium fluoride samples were then investigated. The X-ray diffraction proved that magnesium fluoride nanoparticles were formed with a single-phase structure and no impurities. By using simultaneous fluorination and carbonation technique, crystalline MgF2 nanoparticles with a particle size of 50–60 nm were synthesized at a minimum temperature of 100 °C. Increasing the calcination temperature led to the evaporation of the volatile products and increased the crystallinity and particle size of MgF2 nano-particles. The optimal calcination temperature of 640 °C created a ceramic MgF2 with a hardness of 560 HV, and considerable relative density of 100%, and a high transmittance of over 90% in the 3.2–5.5 μm range. The obtained results, thus, revealed that the transparency of MgF2 ceramics was a function of the porosity and the grain size distribution. The microstructure of hot-pressed MgF2 confirmed a Gaussian grain size distribution in the range of 100–1000 nm, contributing to the enhancement of densification. An intra-granular fracture occurred in magnesium fluoride, which was related to the fine-grained structure of MgF2.