Earth Has Blueberries Too - Universe Today
NASA scientists coined the term "blueberries" to describe the tiny hematite balls found on Mars by Spirit and Opportunity over the last few months - it was one of the most powerful pieces of evidence that liquid water once flowed across the surface of Mars. Researchers from the University of Utah had a hunch these hematite concretions would turn up on the Red Planet, since there are similar conditions in Utah's national parks. The geologists believe the blueberries on Earth were formed 25 million years ago when minerals precipitated from groundwater flowing through sandstone.