Mars’ Red Color Linked to Water-Rich Mineral, Study Finds

New research identifies ferrihydrite, a water-containing iron oxide, as the primary cause of Mars’ iconic red hue, reshaping our understanding of the planet’s ancient environment.

A study published in Nature Communications reveals that ferrihydrite, a water-rich iron oxide, is responsible for Mars' red dust, challenging the previous belief that dry hematite caused the color.
Ferrihydrite forms in the presence of cool water, suggesting Mars had liquid water on its surface earlier than previously thought, potentially over 3 billion years ago.
The findings are based on data from multiple Mars missions, including ESA's Mars Express and NASA's Perseverance rover, combined with laboratory simulations of Martian dust.
Researchers recreated Mars-like dust to confirm ferrihydrite as the best match for the planet's red hue, using advanced grinding and spectral analysis techniques.
The discovery provides new insights into Mars’ wetter past and raises further questions about its habitability, with upcoming sample return missions expected to offer more definitive answers.