Visitors look at the kutnahorite carvings during a jewel and jade expo in Hohhot, capital of north China's Inner Mongolia Autonomous Region, March 7, 2014. [Photo by Deng Hua/Xinhua]

An exhibitor cleans a Shoushan stone carving during a jewel and jade expo in Hohhot, capital of north China's Inner Mongolia Autonomous Region, March 7, 2014. [Photo by Deng Hua/Xinhua]