The homely rocky surface of the closest planet to the Sun may hide a sparkling secret: a layer of diamonds compressed within. Researchers suggest it might be 11 miles deep.
The diamonds might have formed soon after Mercury itself coalesced into a planet about 4.5 billion years agofrom a swirling cloud of dust and gas, in the crucible of a high-pressure, high-temperature environment. At this time, the fledgling planet is believed to have had a crust of graphite, floating over a deep magma ocean.
A team of researchers recreated that searing environment in an experiment, with a machine called an anvil press that's normally used to study how materials behave under extreme pressure but also for the production of synthetic diamonds.
"It's a huge press, which enables us to subject tiny samples at the same high pressure and high temperature that we would expect deep inside the mantle of Mercury, at the boundary between the mantle and the core," said Bernard Charlier, head of the department of geology at the University of Liège in Belgium and a coauthor of a study reporting the findings.
In the 1990s, the talk was all about hauling enormous diamonds back from the asteroid belt. Scientists believe it's abundant out there, including in the pressurized cores of gas giants.
High pressure experiments suggest large amounts of diamonds are formed from methane on the ice giant planets Uranus and Neptune, while some planets in other planetary systems may be almost pure diamond. Diamonds are also found in stars and may have been the first mineral ever to have formed.
They'll never know it isn't moissanite.
Previously:
• Why are diamonds clear, but coal black?
• Why diamonds suck
• Diamonds do not come from coal
• Rare mystery diamonds came from outer space, scientists report
