A partial shutdown of production by rare earth producers in North and South China has led to a 20 percent rise in prices.

The price of Neodymium-praseodymium oxide, a key rare earth mineral, now costs between 340,000 ($54,604) and 360,000 yuan a ton. Many of praseodymium's industrial uses involve filtering yellow from light sources. Dysprosium oxide is 2.8 to 3 million yuan a ton, according to the latest price on Baiinfo, a domestic financial information provider.

Dysprosium is used for its high thermal neutron absorption in making control rods in nuclear reactors and for its high magnetic susceptibility in data storage applications.

The prices are 10 to 20 percent higher than in October this year. There are no signs of price rises for lanthanocerite products, which has massive overcapacity.

The partial shutdown in production is by rare earth producers such as China Minerals Rare Earth Co, Aluminum Corporation of China, Inner Mongolia Baotou Steel Rare-Earth (Group) Hi-Tech Co Ltd and some companies in East China's Jiangsu province

Analysts say it is not clear whether the price increase will remain once full production resumes.