NASA discovers Mercury hides 10-mile-thick layer of diamond

Mercury, the planet closest to the sun, has a 10-mile-thick mantle of pure diamond, according to NASA.

The report, derived from data taken from the NASA MESSENGER probe that orbited the red-hot planet for four years and plunged into its surface in 2015, suggests a 10-mile-thick layer underneath the planet’s crust previously thought to consist of graphite is actually diamond, according to Space.com.