Nation on minerals buying spree

China bought 10,000 metric tons of rare earths in the last week, said two people familiar with the matter, as the country continues to stockpile the metals used in batteries and magnets amid international pressure to ease export quotas.

The State Reserve Bureau paid above-market prices, according to the sources, who asked not to be identified because they weren't authorized to speak publicly about the purchases.

China's move may be an effort to reverse a decline, as the price of at least one kind of rare earth tumbled 76 percent from its 2011 high, according to Peng Bo, an analyst at China Merchants Securities Co.