Earlier this year, researchers found a deposit of rare-earth minerals off the coast of Japan that could supply the world for centuries, according to a study.

The study, published in the journal Nature in April 2,018 says the deposit contains 16 million tons of the valuable metals.

Rare-earth minerals are used in everything from smartphone batteries to electric vehicles. By definition, these minerals contain one or more of 17 metallic rare-earth elements (for those familiar with the periodic table, those are on the second row from the bottom).

These elements are actually plentiful in layers of the Earth’s crust, but are typically widely dispersed. Because of that, it is rare to find any substantial amount of the elements clumped together as extractable minerals, according to the USGS.