In contrast, absence of Fe and Mg promotes polymerization and increases viscosity. Oxygens from adjacent water molecules then repel each other. Undercooling Temperature necessary for nucleation and crystallization to begin, Usually below the predicted crystallization temperature. Each atom gives off energy. If it cannot diffuse away quickly enough T will increase and melting may begin.
Crystal growth is a precarious balance between crystallization and dissolution.
Figure shows Component A depleted near the crystal due to crystallization. This enriches liquid near the crystal in B which must diffuse away. Presence of competing phase B lowers the liquidus temperature and heat of fusion raises the liquid temperature. Textures produced vs. nucleation and growth rate. Hence the crystal uses the next available and less desirable component.