China is retaliating against U.S. tariffs by restricting exports of rare earth minerals. Minerals expert Gracelin Baskaran explains why these little-known-elements are so vital to defense and tech.

MP Materials , which owns the only U.S. rare earths mine, said on Thursday it has stopped shipping the critical minerals to ...

China has tremendous power over the rare earths market. The country has the biggest mines, producing 270,000 metric tons (297 ...