Phase transitions include structural, electrical and magnetic transitions. Examples of structural transitions are the change from one crystal structure to another, the change from an amorphous state to a crystalline state, the glass transition, melting, solidification, cold-crystallization and solid-state curing. Examples of electrical transitions are the change from a metallic state to an insulator state and the change from a normal conducting state to a superconducting state. An example of a magnetic transition is the change from a ferromagnetic state to a paramagnetic state. Phase transitions in general tend to affect the electrical resistivity, thereby allowing resistivity measurements to indicate phase transitions. However, not all phase transitions give rise to a significant change in the electrical resistivity.