Mars crater is 'chock-full' of opal gemstones, hinting at widespread water and possible microbial li

By JoAnna Wendel published 2 days ago

Mysterious "halos" of rock surrounding cracks in a Martian crater may be made of water-rich opal gemstones, a new study suggests.



Light-toned fracture halos as seen crosscutting the bedrock extend into the subsurface. These fracture networks would have served as safe havens from harsh surface conditions in a modern period on Mars. (Image credit: Malin Space Science Systems/NASA/JPL-Caltech)

An ancient, dried-up lake bed on Mars may be teeming with opal gemstones, new data from NASA's Mars Curiosity rover suggests.

Beyond giving the cracked surface of Mars' Gale Crater a semiprecious glint, these opals could be evidence that water and rock have been interacting beneath the Martian surface much more recently than was previously thought, improving the prospects that microbial life once lived there, according to a study published Dec. 19 in the Journal of Geophysical Research: Planets(opens in new tab).

Scientists often focus on water when searching for signs of extraterrestrial life because it's critical for life as we know it. But because water no longer flows on Mars, scientists must hunt for geological signs of the water that once existed there. These signs are present in the Red Planet's rocks and soil, where certain minerals and structures form only where rock and water have interacted.

Researchers spotted one such sign in the past few years around fractures in the Martian surface. Surrounding some of these fractures are "halos" of lighter-colored rock, which researchers found are likely rich in opal. For opal to form, silica-rich rocks must interact with water.

More:
https://www.livescience.com/mars-opal-gemstone-crater