Top 5 'rare earth' minerals: What are they?

Setting off speculation that China is manipulating exports to punish certain trade partners, Beijing announced in July it was slashing its six-month export quota of so-called 'rare earths' by 72 percent. Speculation continued this week with reports of an expanding embargo of the minerals.

But the so-called "rare earths" are neither rare nor does China have a lock on them. Although China produces 97 percent of the world's rare earths, it contains only 30 percent of the world's supply. The United States, Russia, and Australia all have significant reserves of the 17 elements essential in semiconducters, lasers, and other high-tech gadgets.

While mining them has proved uneconomical at usual world prices and environmentally harmful, that may be changing. Click through the following slides to read how rare earths are important to your daily life.

5.Lanthanum

A man looks at Toyota Motor Corp's Prius at its showroom in Tokyo on Feb. 4, 2010. The hybrid car's engine battery uses the rare earth metal of lanthanum. (Kim Kyung-Hoon/Japan)

Drive a hybrid car? Then you're using lanthanum (No. 57 on the periodic table).

Reuters reported last year that a single Toyota Prius electric motor requires 1 kilogram (2.2 lb) of neodymium, and each battery uses 10 to 15 kg (22-33 lb) of lanthanum. "The Prius hybrid automobile is popular for its fuel efficiency, but its electric motor and battery guzzle rare earth metals, a little-known class of elements found in a wide range of gadgets and consumer goods," according to the British news agency.

Lanthanum is also essential in some superconductors, as the Monitor reported in 2008.

Cerium

Dave Mead of Massachusetts stands by the projectors at the Wellfleet Drive-In, which in the 1990s was still using carbon arc lights to project the image. He has to change the rods every 4 reels or after 80 minutes. The rare earth element cerium is used in carbon-arc lighting. (Melanie Stetson Freeman/CSM)

Common as copper, cerium (No. 58 on the periodic table) is one of the most abundant of the rare earth metals.

It is often converted into cerium oxide, which is known as "optician's rouge" for its ability to polish glass and semiconductors. Cerium oxide (CeO2 ) is also essential in catalytic converters, helping to turn smog-causing molecules into carbon dioxide, as well in the massive carbon-arc lighting used on movie sets.

Bloomberg reported recently that cerium oxide prices rose to $36 per kilogram Oct. 19 from about $4.70 a kilogram on April 20, according to Metal-Pages.

Neodymium

James Hetfield of Metallica performs during a concert at the Olympic Stadium in Stockholm in 2007. The concert may not have happened without the rare earth metal of neodymium, which is used in microphones and guitar pick-ups. (Bertil Ericson/Reuters)

You'll never think of a rock concert the same way. Neodymium (atomic No. 60) is most commonly used in magnets for microphones, loudspeakers, in-ear headphones, and guitar and bass guitar pick-ups.

It's also used in modern weapons, sparking concerns over China's corner on the market, Bloomberg reported in September:

“It’s a seller’s market now,” says Bai Baosheng, 43, puffing a cigarette in his office in Baotou, China, where his company sells bags of powder containing a metallic element known as neodymium, vital in tiny magnets that direct the fins of bombs dropped by US Air Force jets in Afghanistan.

... Neodymium, a silvery metal, is essential in a magnetic alloy developed separately by engineers at General Motors Co. in Detroit and Sumitomo Special Metals Co. in Japan in the 1980s. The magnets are now in millions of stereo speakers, computer disk drives, and motors.

Bloomberg recently reported that the price of neodymium has doubled since July to $92 a kilogram, according to Metal-Pages, pushing up the cost of magnets.

Europium

Euro currency is pictured in the regional central bank in Bremen, Germany. The rare earth element of europium, fittingly, is used in the European currency as an anticounterfit measure; a true Euro radiates red under certain conditions.

If you've held a Euro banknote, then you've held europium.

Named after the Western continent, europium (atomic no. 63) is luminescent. For that reason, it's used in Euro banknotes as an anticounterfeiting phosphors. Under certain conditions, the banknote will appear red. Europium is also used in LED screens in TVs for red coloring.

For the Monitor, science reporter Pete Spotts reports: "Europium, for instance, helped drive the shift from black-and-white to color TV by turning the dull reds in early TV screens to reds that popped. Erbium placed at intervals along fiber-optic lines amplifies the light carrying data, allowing it to travel long distances."

Erbium

A fiber optic cable carrying 96 strands of optical fiber capable of transmitting voice and data, is a typical type of cabling that technicians install underground. They commonly use the rare earth element of erbium. (Newscom )

Erbium (atomic no. 68) brings you Dancing With the Stars. Really.

The element is essential in fiber-optic telecommunication cables, which bring cable television and Internet to your homes and apartments.

According to the US Geological Survey, "fiber-optic cables can transmit signals over long distances because they incorporate periodically spaced lengths of erbium-doped fiber that function as laser amplifiers. Er is used in these laser repeaters, despite its high cost (approximately $700/kg), because it alone possesses the required optical properties."