Which NASA rover found hematite spherules nicknamed blueberries on Mars?

Which NASA rover found hematite spherules nicknamed blueberries on Mars? Opportunity. The rover discovered the rounded, grayish spherules at Meridiani Planum soon after landing in January 2004.

The “blueberries” are rich in hematite, an iron oxide. Opportunity’s instruments found that the spheres were embedded in rock and scattered across the surface. Scientists interpreted them as concretions that formed when mineral-rich water moved through sediments, making them important evidence of ancient watery conditions on Mars.

Opportunity landed inside Eagle crater on January 24, 2004, and operated for nearly 15 years, far exceeding its original planned mission of about 90 Martian days. Its investigation of Meridiani Planum helped show that the region once experienced water that was chemically acidic and potentially habitable for some forms of life.

The nickname does not mean the spheres are blue in the ordinary sense. They appeared bluish or gray against Mars’s rusty-red soil in rover images. Spirit was Opportunity’s twin rover, while Curiosity and Perseverance explored different sites and made other discoveries.