Rare earth metals are a collection of 17 chemical elements that rarely exist in pure form. Three important rare earth metals are scandium, gadolinium, and ytterbium. Scandium is mainly used for research and in mercury vapor lamps. Gadolinium is used in alloys for high temperature resistance and oxidation resistance, and in gadolinium yttrium garnets for microwave applications. Ytterbium is used in stress gauges to monitor ground deformations and in alloys to improve strength. Neodymium plays an essential role in miniaturizing devices by creating powerful permanent magnets used in motors, phones, and turbines.