New Delhi, Nov. 3 -- Early last month, China tightened its policy on rare earths. Two of China's biggest players, Baogang Group and Northern Rare Earth, immediately announced sharp price increases of 37%. Other suppliers have indicated even larger increases, resulting in a coordinated tightening of the market.

What are rare earths? Rare earth elements are a set of 17 heavy metals on the periodic table. Fifteen of these, with atomic numbers from 57 to 71, are 'lanthanides.' Two other metals, scandium (Atomic No. 21) and yttrium (Atomic No. 39) are also rare earth elements. These typically occur in various chemical combinations and such minerals are called 'rare earth minerals.' Most often, these minerals are made up of rare earth oxides....