Garnets are rather beautiful little things, particularly when they’re pristine and sizeable enough to be classed as gems. These products of geological extremes turn up in all sorts of environments all over the world, but there’s something strange about those found in riverbeds and soils in Thailand.
Plenty of them appear to have little hollow tubes running through them, a value-decreasing property that was previously blamed on chemical or geological processes. A new PLOS ONE study, however, has an eye-catching new hypothesis as to where these tunnels came from: burrowing microorganisms.
At this point, it’s entirely unclear what type of lifeform specifically may have made these tunnels, and the evidence on which this idea is based still lacks a smoking gun. If the researchers are correct, though, this would make it the first time that such biologically produced tunnels have been found within gemstones.
These intricate tunnels form odd, somewhat chaotic patterns, not conforming to the planes that course through minerals that are forged according to physical and chemical laws.
Some chemical weathering may be involved, but the authors’ paper suggests that to look like these tunnels do, they need “the involvement of an agent that controls the direction.” Garnet is also resistant to physical and chemical weathering by even extremely tough minerals, which certainly implies that life found a way instead.
It’s certainly hard to shake the fact that they sure look like tunnels found in a wide range of environments that were bored out by biological entities. The tunnels are incredibly small, which suggests they could have bacterial architects, but certain types of fungi and even algae could also fit the bill.
Significantly, there’s plenty of organic matter within these garnet tunnels, and a highly sensitive spectroscopy technique revealed them to be decidedly complex. Some appear to be fatty acids, the type that’s found in cell membranes used by various organisms.