Rare earth element
Through the 1960s until the 1980s, a mine in California was the leading producer. Today, the Indian and South African deposits still make some rare earth concentrates, but they are very small compared to the amount being produced in China. China produces over 95% of the world's rare earth supply. Most of this has been done in Inner Mongolia,China's rare earth dominance, Wikinvest. Retrieved on 11 Aug 2010. even though it had only 37% of proven reserves. These numbers have since been lowered to 90% of global production and a proven reserve rate of only 23% by 2012. All of the world's heavy rare earths (such as dysprosium) come from Chinese rare earth sources such as the polymetallic Bayan Obo deposit.Chao E.C.T.et al  1997.  "Sedimentary carbonate‐hosted giant Bayan Obo REE‐Fe‐Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin". United States Geological Survey Publications Warehouse. In 2010, the United States Geological Survey (USGS) released a study which said  the United States had 13 million metric tons of rare earth elements.