China has tremendous power over the rare earths market. The country has the biggest mines, producing 270,000 metric tons (297,624 tons) of minerals last year compared to the 45,000 tons (40,823 metric tons) mined in the U.S. China supplies nearly 90% of the world’s rare earths because it also is home to most of the processing capacity.

The U.S.-China tariff battle is heating up again, with China stopping exports of rare earth minerals and magnets. This will badly hit the manufacture of the iPhone and other Apple products outside of China.

Chinese export limits are energizing a push for more domestic mining of these minerals, which are used in electronics and military applications.