“…This was interpreted by the presence of titanium-rich droplets and the formation of titaniumrich and silicon-rich regions was confirmed later for heat-treated glasses [6,12,13]. These regions can be the starting point for the internal crystallization of the volume of the glass enabling, at higher temperatures, the nucleation of (Mg-Al)-titanate crystals before or simultaneously with a β-quartz solid solution [2][3][4]7,8,12,[14][15][16][17][18][19].…”