rare earth
rare-earth element
lanthanoid
lanthanide
lanthanon

Lutetium is one of the rarest and is the most expensive rare-earth element.

Elements of the Lanthanide series are commonly termed rare-earth elements.

The use of other substances in the core, such as rare-earth elements and Si, are being explored to reduce toxicity.

The site turned out to be rich, however, in rare-earth elements.

Within those ancient rocks are rare-earth elements now valued in applications such as hybrid automobiles and wind turbines.

A second technique developed utilises the natural enrichment of the rare-earth elements in fluorite.

He discovered neodymium and praseodymium (1885), two of the rare-earth elements.

The minerals in question are gadolinite and xenotime, sources of the so-called rare-earth elements.

Locked up inside a lot of them are a number of rare-earth elements.

Rare earth magnets are made from rare-earth elements.