The Department of Defense made a historic investment in MP Materials, a rare earth producer, back in July.MP Materials (MP 0.95%), a lesser-known player in the mining sector, has captured attention following a significant investment from the U.S. government earlier this year. As the operator of one of the only rare earth magnet companies in the United States, MP has found itself in the spotlight amid the U.S.'s ongoing trade war with China. Rare earth materials play a pivotal role in defense, technology, an ...