Definition of "rare-earth" []

• Any of a class of cell membrane proteins that function as intermediaries between hormone receptors and effector enzymes and enable the cell to regulate its metabolism in response to hormonal changes. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Vale representatives said last week at the Brazilian Mining Institute's biannual congress that the company had discovered "safe" radioactive elements at the Salobo site that could be classified as rare-earth minerals."
• "The region is also a key producer of so-called rare-earth elements, which are increasingly in demand in high-tech manufacturing, and are almost exclusively mined in China, which accounts for about 97% of global output."
• "Today, that mine, chock-full of so-called rare-earth metals, is responsible for one of the fastest windfalls in private-equity history: Turning $200 million into a paper profit of about $2.3 billion in just 30 months, or roughly $2.6 million in profit each day."