MP Materials said on Wednesday it would sell $500 million of its common stock, a day after the U.S. rare earths miner inked a supply deal with Apple .

MP Materials announced a $500 million partnership to supply Apple with rare-earth materials from its US mine, sending shares soaring.

The Cupertino tech giant has inked a $500 million deal with Mountain Pass’ owner and operator MP Materials, the two companies announced on Tuesday, in a move that will help Apple onshore a part of its sprawling supply chain.

MP Materials, which has the only operational rare earths mine in the U.S., has drawn interest as a challenger to China's dominance from investors ranging from the Pentagon to tech giant Apple in recent days.