Diamond found containing a rare ice crystal!

Inclusions in diamonds brought up from deep within the earth provide valuable clues to the mineralogy and chemistry of parts of Earth that we cannot otherwise sample.  Earlier this month researchers stumbled onto a native ice-VII sample by accident. Inside a diamond formed deep in the Earth’s mantle. As much as 400 miles beneath the crust.  Though ice-VII was known to form in space, it had only been created in lab conditions on Earth.

More about Ice-VII

What we know as ice is just one of many chemical structures that frozen water can take. The ice we are familiar with is known as ice-I in which water freezes in a hexagonal shape. But as water is compressed, the molecules begin to take on different shapes. Ice-VII has a cubic molecular shape and is one and a half times as dense as regular ice. Which until now has never been found naturally on Earth,

The mantle is very hot, so there’s no way for ice to form there. In very rare cases, as a diamond travels up through the mantle and crust to the Earth’s surface, they maintain their tight lattice structure, and the water inside them is exposed to low enough temperatures that ice-VII can form.

“Water in diamonds is not unknown, but finding this very high-pressure form of water ice intact, that was really fortuitous,” George Rossman, a mineralogist at Caltech, told the Los Angeles Times. “That’s what you call discovery.”