2.5 billion-year-old traces of life locked inside primeval ruby

A new study has revealed that ancient life was preserved in a 2.5 billion-year old ruby from Greenland.
Greenland is home to the planet's oldest rubies. These sparkling red gemstones are made of corundum, a transparent mineral that contains a transparent red pigment. A group of researchers was searching for rubies within the North Atlantic Craton in southern Greenland when they discovered graphite. This pure carbon form may have been the remnants of ancient microbial activity.

Chris Yakymchuk (a professor of Earth and Environmental Sciences at University of Waterloo, Ontario, Canada) said that the graphite in this ruby was truly unique. It's the first time that we have seen evidence of ancient life in rocks containing ruby-bearing rubies.

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After analyzing the carbon content of graphite in different forms, the team concluded that it was derived from an ancient form of life. The planet's carbon has a total mass of more than 98%. However, some carbon atoms have a heavier mass, with 13 to 14 atomic masses units.

Yakymchuk stated that living matter prefers lighter carbon atoms, as they require less energy to integrate into cells. We concluded that the graphite contained more carbon-12 than normal, which suggests that carbon atoms once belonged to ancient life. This is most likely due to dead microorganisms like cyanobacteria.

The planet didn't have enough oxygen at the time that this ancient bacteria lived. This was an essential element for complex life. Therefore, tiny microbes and algae films were the only viable life forms. Cyanobacteria are believed to have been the first living organisms on Earth. They converted sunlight into chemical energy over billions of years, eventually producing the oxygen needed for complex life, Live Science reported.

Although it is ancient, the graphite-containing diamond is not the oldest evidence of human existence. Live Science reported that there are many studies, some of which are heatedly debated, that claim they have found the oldest evidence for life going back to more than 3 billion years.

However, this is the first time that ancient life has been discovered in rubies. Yakymchuk stated that graphite gives us additional clues about how rubies formed in this area. This is something that is difficult to establish based solely on the ruby's chemical composition and colour.

The secret ingredient to the formation of rubies may be life. Research revealed that graphite alters the chemical composition of rocks, creating the conditions necessary for rubies to grow.

These findings were published in the November issue Of Ore Geology Reviews.

Original publication on Live Science