The effect of varying the SiO2 content on the crystallization and microstructural behavior of strontium containing glasses based on the system SrO.4MgO.Al2O3.6SiO2-2MgF2 was investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). DTA analysis revealed that the glass transition temperature (T") and crystallization peak temperature (7"p) increased by increasing silica content. It was also shown that the higher the silica content, the lower is the aspect ratio of the fluorophlogopite crystals and appearance of pores in the body. The analysis of X-ray diffraction patterns revealed that strontium fluorophlogopite crystals exist as major phase in all heat treatment temperatures. © 2016 Scientific Publishers. All rights reserved.