New Delhi, July 16 -- MP Materials, which runs the only American rare earths mine, announced a new $500 million agreement with tech giant Apple on Tuesday to produce more of the powerful magnets used in iPhones as well as other high-tech products like electric vehicles.

This news comes on the heels of last week's announcement that the U.S. Defense Department agreed to invest $400 million in shares of the Las Vegas-based company, establish a floor for the price of key elements and ensure that all of the magnets made at a new plant in the first 10 years are purchased.

That unusual direct investment in the company makes the government the largest shareholder in MP Materials.

"This is the kind of long-term commitment needed to reshape glob...