Donald Trump's claim that the mineral deal he hopes to sign with Ukraine might be worth a trillion dollars has been called into question due to a US Geological Survey stating that Ukraine 'isn't known to hold any reserves of main rare earths'.

The Ukrainian Geological Survey last year claimed that the war-torn country had reserves of rare minerals - but US scientists made no mention of such sought-after earths in their own US Geological Survey four years ago.

'What Ukraine has is scorched earth; what it doesn't have is rare earths,' Bloomberg's regional expert Javier Blas said.

Rare earths are a group of 17 metals used to make magnets that turn power into motion for electric vehicles, cell phones, missile systems, and other electronics. There are no viable substitutes.

According to the Institute of Geology, Ukraine possesses rare earth elements such as lanthanum and cerium, used in TVs and lighting; neodymium, used in wind turbines and EV batteries; and erbium and yttrium, whose applications range from nuclear power to lasers.