These Dazzling Gemstones Are Home to Microbes

In a discovery that sounds like the premise for a children’s book, scientists have identified tiny habitats, created and once inhabited by microorganisms, inside gemstones.

Magnus Ivarsson, lead author of a PLOS ONE study published Wednesday about these bejeweled micro-homes, said the discovery marks the first time that traces of life have been detected within gemstones, specifically gem-quality garnets.

“Usually microbes bore and colonize minerals and materials [that are] not so hard as gemstones,” Ivarsson, a biologist at the University of Southern Denmark, told me in an email.

Yet these precious stones, retrieved from soil and river sediments in Thailand, are riddled with tunnel networks that had been previously chalked up to non-biological forces, especially erosive weathering processes associated with riverbed environments. After observing the gems under sensitive microscopes and spectrometers, however, Ivarsson and his colleagues found that the tunnels contained traces of fatty acids likely left behind by microscopic creatures.

While some portions of the garnet lair may have formed abiotically, the complex network of tunnels—which includes passages linking them—suggest it was at least partly developed by endoliths, a group of microorganisms known to live within hard materials like rock, shell, and bone.

Endoliths are often able to survive in inhospitable conditions by feeding on minerals like iron, potassium, and sulfur. It’s possible that the residents of the garnet burrow subsisted on the gem’s iron deposits to survive, but it would be premature to make any conclusions about these organisms without live observations, Ivarsson said.

“We would need to go back and sample for DNA/RNA and isolation of endoliths so we can cultivate them and use in laboratory experiments,” he told me. “We have discussed returning to Thailand for such a mission.”

If scientists are able to find and sustain garnet microbe colonies for study, the research could have repercussions beyond Earth. Endoliths are especially interesting to astrobiologists, scientists that study life’s origins and evolution in the universe, because these creatures thrive in the kind of stark rocky environments thought to be plentiful on alien terrestrial worlds.

The only thing more mind-boggling than finding humble microbes cozying up inside a precious ornamental stone is the idea that planets across the Milky Way may support similarly bedazzled ecosystems.

Get six of our favorite Motherboard stories every day by signing up for our newsletter.