Scientists from the University of Waterloo studying how rubies are formed discovered the residue of a microorganism inside a 2.5 billion-year-old gemstone.
The team found a ruby that contained graphite while working in Greenland, which is home to some of the oldest known deposits of colored gemstones. Graphite is made of pure carbon and analysis of its atomic mass indicated that it was produced by an ancient lifeform.
Carbon-12 atoms are easier to integrate into living cells than heavier carbon-13 or carbon-14 atoms. The ruby's graphite had an elevated level of carbon-12, which indicated it was once alive. There wasn't much oxygen in Earth's atmosphere when the gem was formed, meaning the microorganism was likely a cyanobacteria or part of an algae film.
“The graphite inside this ruby is really unique," Waterloo professor of Earth and Environmental Sciences Chris Yakymchuk said in a press release. "It’s the first time we’ve seen evidence of ancient life in ruby-bearing rocks. 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 color and chemical composition.”
The team discovered that the microorganisms actually allowed the rubies to form by changing the chemical composition of nearby rocks. The results of the study were recently published in Ore Geology Reviews.
Samantha Nelson is a freelance writer for IGN. You can find her on Twitter @samanthanelson1.
