recrystallization

Recrystallization is a key process in the formation of metamorphic rocks. It occurs when existing rocks, called protoliths, are subjected to changes in temperature and pressure deep within the Earth. These conditions cause the minerals within the rock to change, break down, and reform into new minerals or new crystal structures, without melting. This process alters the rock's texture and mineral composition, creating the characteristic features of metamorphic rocks, such as foliation or preferred mineral orientation. The original chemical composition of the protolith significantly influences the types of metamorphic minerals that form during recrystallization.123