Rare earths are among the most critical raw materials on the planet, deeply embedded in the technologies that underpin modern life. Yet few people had even heard of them until the eruption of the US-China trade war thrust them into the limelight.

The announcement offered hope of a reprieve on shortages that have hit American industry, and came after President Trump said he signed a deal with China.

The threat of mass shutdowns across the automotive supply chain is fading as Chinese rare earth magnets begin to flow, though automakers and suppliers say production plans still face uncertainties and a continued risk of shortages.