New Delhi, Oct. 12 -- For months, US and China appeared to simmer their trade tensions by striking deals and replacing warnings of an economic "war" with words like "thaw" and "truce".

The hostilities now appear to return to a full boil. And, at the centre of this is rare earth minerals.

The US-China tussle over rare earths precedes the current Donald Trump administration, and has been a contentious topic between the countries for years.

But what even are rare earths and why are they so important? We explain.

Rare earths are a set of 17 lustrous silvery-white soft heavy metallic elements in the periodic table, made up of scandium, yttrium and the lanthanides.

The 15 lanthanides, along with scandium and yttrium, are usually included a...