Analyzing some of the world's oldest colored gemstones, researchers from the University of Waterloo, Canada, discovered carbon residues that were once ancient life, encased in 2.5 billion-year-old rubies.
The research team, led by Chris Yakymchuk, professor of Earth and Environmental Sciences at Waterloo, set out to study the ruby's geology to better understand the conditions required for the ruby's formation.
During research in Greenland, which studied the world's oldest ruby deposit, the team discovered ruby samples containing graphite, a mineral made of pure carbon. Analysis of this carbon shows that it is a remnant of early life on Earth.
"The graphite in these rubies is truly unique. This is the first time we have seen evidence of ancient life in rubies," Yakymchuk said as quoted by Terra Daily as seen on Friday (29/10/2021).
"The presence of graphite also gives us more clues to determine how rubies formed at this location, something that is not possible directly based on the color and chemical composition of the rubies."
The presence of graphite allowed the researchers to analyze a property called isotopic composition of carbon atoms, which measures the relative number of different carbon atoms. More than 98% of all carbon atoms have a mass of 12 atomic mass units, but some carbon atoms are heavier, with a mass of 13 or 14 atomic mass units.
"Living matter is preferentially made up of lighter carbon atoms because they require less energy to get into cells," says Yakymchuk.
"Based on this increase in the amount of carbon-12 in graphite, we conclude that these carbon atoms lived in ancient times," he continued.
This graphite was found in rocks more than 2.5 billion years ago, when there was not yet abundant oxygen in the atmosphere, and life existed only in microorganisms and algae layers.
During this research, Yakymchuk's team discovered that this graphite not only linked gemstones to ancient life, but also altered the chemistry of the surrounding rock to create favorable conditions for the growth of rubies. Without it, the team's modeling suggests it is unlikely that any rubies formed at this location.