Investor interest in rare-earth minerals is rising, a source of strength for shares in the rare-earth miner MP Materials. The stock rose Friday after jumping late Thursday following a Bloomberg report that the Defense Department might provide additional capital to boost production.

The U.S. trade "deal" with China highlights how dependent Americans are on Chinese rare earth minerals, creating an economic vulnerability.

The US trade war with China has a major sticking point: rare earths minerals. Last month, President Donald Trump said the United States needed Greenland “very badly,” renewing his threat to annex the Danish territory.