In materials science, polymorphism is the ability of a solid material to exist in more than one form or crystal structure. Polymorphism can be found in any crystalline material including polymers, minerals, and metals. It is related to allotropy, which refers to chemical elements. The complete morphology of a material is described by polymorphism and other variables such as crystal habit, amorphous fraction or crystallographic defects. Polymorphism is important in fields such as pharmaceuticals, agrochemicals, pigments, dyes, foods, and explosives.