Rare Earth Elements 101.

Rare earth elements occupy 17 spots on the periodic table. The U.S. government has designated them as "strategic minerals" and therefore vital for national defense.

"Rare" is somewhat of a misnomer because they are found throughout the world in high enough concentrations for mining. For the most part, the 17 rare earths are found together, but some deposits have higher concentrations of some elements than others. Separating them from their host rock and each other is a complex, multi-step process.

They are divided into two further categories depending on their atomic numbers--"light rare earths" and "heavy rare earths"--with the heavy elements considered the most valuable. There is some debate within scientific circles as to which elements belong in which category.

Their importance as building blocks for modern technology is evolving as researchers continue to find uses for them in such everyday items as smartphones, fiber-optics and medical equipment such as MRIs.

However, the application driving the current rush to mine and refine rare earths are high-performance magnets manufactured with neodymium (Nd), dysprosium (Dy), samarium (Sm) and sometimes (Ho) holmium. These magnets are needed to supply the growing market in electric engines along with computer hard disk drives, precision-guided munitions and wind turbines.

The following is a list of the 17 elements and some of their uses in modern technology.

21

Sc

Scandium

Found in abundance but low global production levels have limited the development of applications.

USES: dental lasers; solid oxide fuel cells; aluminum alloys used in baseball bats; bicycle frames; gun cylinders.

39

Y

Yttrium

Created red color in 1960s TV sets. Also found in lunar rocks collected by Apollo astronauts.

USES: superconducting material; cancer treatment; lithium-ion batteries; spark plugs; camera lenses.

57

La

Lanthanum

Applications often overlap with cerium.

USES: nickel metal hydride (NiMH) batteries; petroleum refinement; automobile catalytic converters.

58

Ce

Cerium

The most abundant rare earth.

USES: decolorizing and polishing glass; arc-lights; making aluminum alloys.

59

Pr

Praseodymium

Properties used to give ceramics and glasses yellow/green color.

USES: combined with nickel to make alloys for aircraft engines; nickel metal hydride batteries; fiber-optic amplifier; magnets.

61

Pm

Promethium

The one "non"commercial" rare earth element. Rare in nature; mostly produced in laboratories.

USES: atomic...