(Reuters) - The rare earths are a relatively abundant group of 17 chemical elements, but economically viable deposits are rare.
Prices of the elements, which tumbled after a speculative bubble burst last year, are likely to erode further as new supplies hit the market and exports edge higher from dominant producer China due to weak demand at home.
Here are some facts on rare earths and their uses:
WHAT ARE THE RARE EARTHS?
There are 17 rare earth elements, with 15 chemically-related elements divided into light and heavy rare earth elements, while the other two, scandium and yttrium, exhibit similar properties.
Light elements are: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium.
Heavy elements are: gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium.
BIGGEST PRODUCERS, RESOURCES
China produces more than 90 percent of global supplies and has about half of global reserves. The biggest producer is Inner Mongolia-based Baotou Rare Earth Co 600111.SS.
Russia and the United States have about 17 percent and 12 percent of global reserves respectively. Outside China, the biggest producer is U.S.-listed Molycorp MCP.N, which has reopened the Mountain Pass mine in California. Australia's Lynas LYC.AX is due to launch a plant in Malaysia this year.
BIGGEST CONSUMERS, USES
China, Japan and the United States are the biggest consumers. Below is a summary of rare earth industrial applications and some areas where they are used:
MAGNETS - This is the biggest use, taking up 21 percent of demand, forecast to expand to 26 percent by 2015, for use in wind turbines, hybrid vehicles, earphones and computer hard drives. Neodymium, praseodymium and dysprosium are needed.
CATALYSTS - Petroleum cracking catalysts and auto catalysts use lanthanum and cerium. This use is expected to decline.
PHOSPHORS - These are necessary for the production of television sets and energy-efficient lamps. This is one of the smallest sectors by volume, at about 7 percent, but the largest sector by value, at 30-40 percent, as europium and terbium are among the least common rare earths.
GLASS AND POLISHING - Cerium is used in ultra-violet light filtering. It is also used in glass polishing, a rapidly growing sector that is based on the unique chemical and mechanical properties of cerium.
METAL ALLOYS - Rare earths are used to make super alloys, accounting for about 18 percent of demand, for products such as gas turbines and electric generators. Nickel metal hydride rechargeable batteries are the main driver of demand and could put pressure on lanthanum supply.
Sources: Company websites, USGS, Thomson Reuters (Compiled by Eric Onstad, James Regan, Julie Gordon and Leonora Walet)
Reporting by Eric Onstad; editing by David Stamp
Our Standards: The Thomson Reuters Trust Principles.