rare earth 101: light and heavy

Light rare earths: cerium(铈), lanthanum (镧), praseodymium (镨), neodymium (钕), samarium (钐)
Heavy elements: dysprosium (镝), terbium(铽), europium (铕)
Light rare earths are used in lower-technology applications like oil refining and glass manufacturing.
Heavy rare earth elements are vital to high-tech products, such as iPhones, flat-panel TV, hybrid cars and wind-power turbines.
Source: Keith Bradsher, China Plans to Reduce its Exports of Minerals, New York Times. http://www.nytimes.com/2010/10/19/business/global/19mineral.html

Lynas, the promisting Australian rare earth producer, is based in Mt Weld. “Mt Weld, with its very high grade contains light Rare Earths and is also high in Europium, a heavy Rare Earth.” Source: Lynas Corporation website