NASA’s Curiosity rover discovered rocks made of pure sulfur on Mars, one of the six elemental building blocks of life, in May, according to CNN. Curiosity project scientist, Ashwin Vasavada, told CNN the discovery was “mind-blowing.” “I think it’s the strangest find of the whole mission and the most unexpected,” he added. The team reportedly saw white rocks during their decade-long summit of Mount Sharp, and began moving toward them. The detour took the rover over a rock, which broke under the rover’s 1-ton weight, revealing shiny green and yellow crystals, never seen on Mars. “I have to say, there’s a lot of luck involved here. Not every rock has something interesting inside,” Vasavada said of the discovery. Using instruments in the rover, researchers were able to determine the rock contained pure sulfur. NASA’s previous rover, Spirit, which rolled around the red planet from 2004 to 2011, also made an accidental discovery when a wheel broke and the team began reversing the rover, revealing the trail of pure silica on the ground. The team, inspired their Spirit discovery, turned the rover around after breaking the rock to discover the sulfur.