Mercury may have a layer of diamond beneath its grey surface

A thick layer of diamonds may be hidden hundreds of kilometres below the surface of Mercury, according to an experiment recreating early conditions on the solar system’s smallest planet.

We already know that Mercury is rich in carbon, the element that makes up diamonds, thanks to observations by NASA’s Messenger orbiter, which revealed a surface covered in graphite.  This carbon is likely to be spread throughout the planet’s interior, where its exact form will depend on the temperature and pressure at each location.…