NASA scientists said they were “surprised” when the Mars rover Curiosity cracked open a rock and found it contained pure sulfur crystals, the space agency said Thursday.

“Pure sulfur doesn't smell,” the Curiosity rover's social media accounts tweeted, saying the discovery of elemental sulfur “is something we've never seen before on Mars.” (Related article: Crew in simulated Mars environment escapes NASA habitat after one year)

*crunch* I ran over a rock and there was a crystal in it!

It's pure sulfur (it has no smell). Elemental sulfur is something we've never seen before on Mars. We don't know much about these yellow crystals yet, but my team is excited to find out. https://t.co/Am07DuXpPX pic.twitter.com/coIqWWGGJq

— Curiosity Rover (@MarsCuriosity) July 18, 2024

“We don't know much about these yellow crystals yet, but my team is excited to explore,” the rover tweeted.

NASA scientists are still unsure “how elemental sulfur relates to other sulfur-based minerals” in the area where the rocks were found. according to All discoveries so far have been “sulfur-based minerals, meaning they are a mixture of sulfur and other materials,” NASA added in a press release.

Following the unprecedented discovery, the rover discovered “a bright chunk of rock similar to what the rover crushed,” according to a press release.

NASA will send the Curiosity rover to explore “sulfate-rich” regions of Mars in October 2023, according to a press release.

“Finding a rock block made of pure sulfur is like finding an oasis in the desert,” Ashwin Vasavada, Curiosity's project scientist, said in a press release. “It can't be there, so you have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting.”