A rough diamond found in Brazil and worth only about $20 could be a hint at vast amounts of water hidden under the Earth's surface.

Containing a rare mineral previously only seen from meteorites, the diamond represents a large portion of the Earth's interior portion and could mean that the deep Earth holds as much water as is found in all the oceans.

The gem has water-containing minerals that scientists believe formed as deep as 370 miles inside the Earth, implying that water could be trapped in the interior of our planet, BBC News reported.

Publishing their findings in the journal Nature, a Canadian research team studied the diamond found in Central-West Brazil to discover ringwoodite, a mineral believed to form only 250 miles or more below the Earth's surface.

 "The discovery highlights the unique value of natural diamonds in trapping and preserving fragments of the deep Earth," Graham Pearson, who led the project, told BBC News.

"It's incredible to think that, as you hold this sample in your hand, the residual pressure at the interface between the diamond and the inclusion is 20,000 atmospheres."

Diamonds come to the Earth's surface when volcanic rocks called kimberlites violently erupt and rise from the deep.

The gem's discovery marked the first time ringwoodite from this planet has been seen, according to BBC News. Containing around 1 percent water, ringwoodite accounts for a huge layer of the deep Earth and likely means that large amounts of water are contained there.

The water isn't sloshing around inside the Earth; instead, it's believed to be trapped inside diamonds like the one found in Juina, Brazil.

"It's not a Jules Verne-style ocean you can sail a boat on," noted Pearson, a geologist who studied the stone at the University of Alberta, as quoted by The Guardian.

"It's a fairly ugly diamond. It looks like it's been to hell and back," Pearson described the gemstone.

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