Are There Diamonds on Mercury?

The planet Mercury could have "a layer of diamonds," reports CNN, citing new research suggesting that about 310 miles (500 kilometers) below the surface...could be a layer of diamonds 11 miles (18 kilometers) thick. And the study's co-author believes lava might carry some of those diamonds up to the surface:The diamonds might have formed soon after Mercury itself coalesced into a planet about 4.5 billion years ago from 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 Liege in Belgium and a coauthor of a study reporting the findings. The team inserted a synthetic mixture of elements - including silicon, titanium, magnesium and aluminum - inside a graphite capsule, mimicking the theorized composition of Mercury's interior in its early days. The researchers then subjected the capsule to pressures almost 70,000 times greater than those found on Earth's surface and temperatures up to 2,000 degrees Celsius (3,630 degrees Fahrenheit), replicating the conditions likely found near Mercury's core billions of years ago. After the sample melted, the scientists looked at changes in the chemistry and minerals under an electron microscope and noted that the graphite had turned into diamond crystals. The researchers believe this mechanism "can not only give us more insight into the secrets hidden below Mercury's surface, but on planetary evolution and the internal structure of exoplanets with similar characteristics."

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