An ancient ruby and some graphite, a mineral famous for its use in pencils, reveals a history of life on Earth billions of years ago. It is a story that connects the weight of carbon atoms and a time in the history of our planet when life was made up of microorganisms.
A research team led by geologist Chris Yakymchuk of the University of Waterloo in Canada studied a 2.5 billion-year-old Greenland ruby that contained graphite, a form of pure carbon. “The graphite inside this ruby is truly unique. This is the first time we see evidence of ancient life in ruby rocks,” Yakymchuk said in a statement Thursday.
The team published a study on ruby in the journal Ore Geology Reviews. It took a few detectives to go from discovering graphite to determining that it was probably formed from microorganisms.
Not all carbon atoms are the same; some are heavier than others. “Living matter is preferably made up of lighter carbon atoms because they require less energy to be incorporated into cells,” Yakymchuk said. “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 research team established links between graphite and ruby formation, suggesting that graphite created favorable conditions for ruby growth. We can therefore thank these ancient microorganisms for their contribution to the gemstone dossier and for the fascinating glimpse into the distant past of life on Earth.