(NewsNation) — The planet Mercury might have a layer of diamonds sitting hundreds of miles below its surface, a new study published last month in Nature Communications states.

“Many years ago, I noticed that Mercury’s extremely high carbon content might have significant implications,” Dr. Yanhao Lin, one of the co-authors of the study from the Center for High Pressure Science and Technology Advanced Research in Beijing, told Phys.org. “It made me realize that something special probably happened within its interior.”

NASA’s MESSENGER spacecraft, which orbited Mercury for years, identified abundant carbon on its surface, which the study says is the remnants of graphite that floated to the planet’s crust. This suggests Mercury’s magma ocean and core were once saturated in carbon, according to researchers, which then formed the graphite crust as the planet cooled down.

However, researchers challenged the assumption that graphite was the only stable carbon-bearing phase Mercury experienced as its middle layer cooled and solidified, Phys.org wrote, especially as new studies propose that Mercury’s core-mantle boundary is deeper than previously thought. If these studies are true, conditions on the planet would allow carbon to crystallize into diamond.

Researchers, using high pressure-temperature experiments, thermodynamic models and the most recent geophysical models of the internal structure of Mercury, recreated the planet’s interior and re-evaluated its carbon speciation.

“Here we show it is possible, though statistically unlikely, that diamond was stable in the magma ocean,” the scientists wrote. “However, the formation of a solid inner core caused diamond to crystallize from the cooling molten core, (with the) formation of a diamond layer becoming thicker with time.”