NASA's Perseverance rover has encountered another rock on Mars that has left scientists puzzled.

Named "St. Pauls Bay" by the mission team, the Mars rock features hundreds of millimeter-size dark gray spheres, some of which have tiny pinholes. Perseverance discovered this rock on March 11 on the rim of the Jezero Crater, an ancient lakebed that the rover has been exploring since 2021 for signs of past microbial life. Scientists say determining the geological origins of this area's features could provide valuable insights into how rocks in the region evolved over billions of years.

"Placing these features in geologic context will be critical for understanding their origin, and determining their significance for the geological history of the Jezero crater rim and beyond," the Perseverance team wrote in a statement.