Scientists discover trace of ancient life in a 2.5 billion-year-old ruby - CNN

"Based on the increased amount of carbon-12 in this graphite, we concluded that the carbon atoms were once ancient life, most likely dead microorganisms such as cyanobacteria."

The scientists found the rock in Greenland while studying the geology of rubies to better understand the conditions necessary for their formation.

The team also found that the graphite likely changed the chemistry of the surrounding rocks to create favorable conditions for ruby growth.

"The presence of graphite also gives us more clues to determine how rubies formed at this location, something that is impossible to do directly based on a ruby's colour and chemical composition," Yakymchuk said in the statement.

The research was published in Ore Geology Reviews last week.