Cicada In Gemstone May Help Hunt For Extraterrestrial Life

Jul 6, 2020

It's not uncommon to find insects trapped in amber. In fact, an entire movie franchise has been built around it. But now, scientists have confirmed the existence of a bug inside a piece of opal. The find could aid in the hunt for life on Mars.

The gem came from an Indonesian mine, and is from the Pleistocene epoch, which lasted about five to 10 million years ago. Opals are commonly formed by rock weathering: minerals collect and form a silica gel, which eventually hardens.

Researchers suspected the insect was a cicada, and contacted a St. Joseph University professor who is an expert on cicadas. "It looks like this cicada nymph or possible shed skin - it's hard to tell - was preserved in this little cavity underground," Gene Kritsky says.

The preserved cicada isn't easily recognizable to the eye. "It was observed using a process called X-ray tomography, which is a new kind of high-resolution scanner. It allowed us to see a lot of detail," Kritsky says.

Just finding the bug inside the opal is exciting by itself, he says. But there's more to the story.

"We now know that the next landing sites on Mars contains opaline silica. That means if you want to look for fossils on Mars, one of the places you can look is in the opals on Mars," Kritsky says. "The implications of this discovery extend beyond the pure obvious 'Oh this is kinda neat, we're finding insects in opal.' The broader implications are that it may help us understand some places to look if we want to find evidence of fossil life on extraterrestrial planets."

The discovery opens up the possibility that there's more insects trapped in opals and haven't been noticed yet. "We could look at larger pieces with X-ray tomography to see if there's some inclusions inside those," Kritsky says. "That's the next step. We've seen bits of plant matter in opal. This is opening up a whole new area for possible examination of fossil material."

Kritsky joined the team of researchers from France, the Czech Republic, and the United States, because of his experience with cicadas.