To most of us, ice is just ice. But scientists have categorized no less than 16 types, created under different conditions and featuring different crystalline structures. Most of these have only been created in the lab, but now, geoscientists at the University of Nevada Las Vegas (UNLV) have discovered a type known as Ice VII (seven) locked inside diamonds. This marks the first time the substance has been directly detected in nature, and it suggests that the Earth's mantle is home to huge pockets of water.

Around 74,000 years ago, the Toba supervolcano erupted on the Indonesian island of Sumatra. It was the biggest volcanic eruption of the last 2 million years, unleashing 2,800 cubic kilometers of magma. That’s enough to bury the entire United States in a foot-thick layer of ash and rock.

Imagine a year without summer. The sky turns gray during the day and glows a sinister red at night. Trees wither and start to fall, all vegetation dries down and becomes a desolate shadow of its former self. Animals also start to suffer and thin down, and the damage propagates up the food chain, wiping out entire ecosystems. The same cycle repeats year after year, with no visible end in sight.

The team, led by University of Nevada, Las Vegas geoscientist Oliver Tschauner, found inclusions of the high-pressure form of water called Ice-VII in natural diamonds sourced from between 255 and 410 miles (410-660 km) depth.

A team of researchers has discovered ice crystals in a diamond. Probably not a huge discovery, you may think, but this ice, names Ice-VII, is coming from the Earth’s mantle and has been supposed, until now, that it only naturally exists on other planets and their moons and can only be made in a lab.

The discovery of Ice VII in mantle diamonds suggests the possibility of the Earth having water pockets in the mantle. What could this mean, and why is this important?

Supervolcanoes have the power to cough up enough ash to coat entire continents. They emit waves of hot gas, rocks and ash that flow down their slopes at speeds so great they strip away vegetation and kill anyone in their path. And they carve vast depressions in the planet, leaving permanent scars.

Imagine a year in Africa that summer never arrives. The sky takes on a gray hue during the day and glows red at night. Flowers do not bloom. Trees die in the winter. Large mammals like antelope become thin, starve and provide little fat to the predators (carnivores and human hunters) that depend on them. Then, this same disheartening cycle repeats itself, year after year. This is a picture of life on earth after the eruption of the super-volcano, Mount Toba in Indonesia, about 74,000 years ago. In a paper published this week in Nature, scientists show that early modern humans on the coast of South Africa thrived through this event.

Deep within the hot interior of the planet, ice lurks. Now, a form of super-compact ice, found embedded in diamonds, offers the first direct clue that there is abundant water more than 610 kilometers deep in the mantle.

Diamonds, the super-strong and brilliant crystals of carbon atoms produced under the Earth’s crushing pressures, are typically valued for their beauty and durability. But scientists also value them for another reason: They contain all kinds of hidden messages about the Earth’s mantle. You just need the right tools to read them.

Small pockets of water exist deep beneath Earth’s surface, according to an analysis of diamonds belched from hundreds of kilometers within our planet. The work, which also identifies a weird form of crystallized water known as ice VII, suggests that material may circulate more freely at some depths within Earth than previously thought. Geophysical models of that flow, which ultimately influences the frequency of earthquakes driven by the scraping of tectonic plates at Earth’s surface, may need to be substantially tweaked, scientists say. Such models also help scientists estimate the long-term rates of heat flow through Earth’s surface and into space.

A new report published today in Science suggests that pockets of liquid water may exist up to 500 miles beneath Earth’s surface—far deeper that previous estimates. This conclusion was reached after scientists discovered a rare form of crystalized water known as ice VII in diamond samples recovered in Africa and China. These ice VII samples are the first time this form of crystalized water has been seen in nature and led the International Mineralogical Association to declare ice VII as a new type of mineral.