Formation of metal microcrystals in glass forming melts has attracted scientific interest for many years because the optical properties of glasses are significnatly influenced by the morphology and size distribution of the metallic particles incorporated. To get a deeper insight into the mechanism of formation of metallic microcrystals, a theoretical description is employed based on thermodynamic considerations and on kinetic derivations in the framework of the classical theory of nucleation. The theoretical analysis indicates two possible ways of formation: direct segregation of crystalline metallic clusters or, alternatively, initial separation of liquid phase clusters followed by the subsequent crystallisation of the droplets formed. The latter path is a manifestation of Ostwald's Rule of Stages which is considered here.
