Siegel told CNBC's "Squawk Box" that the U.S. should create a rare earth minerals reserve as rising trade tensions threaten global supply chains.

Stocks tied to rare earths jumped after Trump threatened countermeasures against China, noting the country was holding the world "captive" over the metals.

Siegel told CNBC's "Squawk Box" that the U.S. should create a rare earth minerals reserve as rising trade tensions threaten global supply chains.

The last week could just be a preview to China weaponizing its entire supply chain, the investor told Fortune.

China will not allow the export of rare earth materials for use by foreign militaries under restrictions announced last week.