The Earth has five oceans, right? There’s the Atlantic, Pacific, Indian, Arctic, and Southern Oceans. Even the Southern Ocean is relatively new so you may have learned that Earth only has four. But now we have evidence of water deep inside the planet, too. A lot of water in fact—potentially more than the volume of all of the oceans we already know about combined. Scientists confirmed the presence of water thanks to a diamond found in Botswana. The gem originated more than 400 miles deep in the Earth and has tiny little imperfections from minerals and water from that deep layer inside the planet where it formed.

GPA Photo Archive

A team of scientists from the United States, Italy, and Germany published the results in the peer-reviewed journal Nature Geoscience. We learned about it on Mashable. The press release also includes details about the so-called deep water cycle that plays a role in plate tectonics, volcanic activity, and earthquakes.

Samples from far below the Earth’s crust are hard to come by. The deepest operations to bore under the Earth’s surface only reach about seven miles down. Below the crust lies the mantle and many other layers separating the surface from the Earth’s center 4,000 miles down. Whether our planet also includes water in those layers has long been debated. The minerals inside the diamond reveal its formation deep within the Earth and show that water exists there as well.