Rare earth ore. Handful of ore mined at the Mountain Pass rare earth mine. This mine is located in the Clark Mountain Range, California, USA. Operated by Molycorp, it is the only rare earth oxide (REO) mine in the Western hemisphere and the world's largest such mine outside of China. It re-opened in 2010. Samples like these are processed and analysed to design the chemical and engineering processes used to extract the rare earth elements. These elements (including praseodymium, neodymium, yttrium, and terbium) are used in a range of high-tech equipment. Photographed in October 2011.