Niobium is used in steel and 7 times more valuable than copper.
BLOOMBERG.COM

The world’s mines and steel plants got so devalued during the commodity slump that some were just given away by owners struggling to cut losses or debt. But there’s at least one metal that’s been attracting a lot of attention. Niobium -- named for a Greek goddess who became a symbol of the tragic mourning mother -- is used to produce stronger, lighter steel for industrial pipes and aircraft parts. It is mined in only three places on Earth, and the price of every kilogram is seven times higher than copper.

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