A study suggests Mars takes its red hue from a type of mineral that forms in cool water, which could reveal insights about whether Mars was ever able to support life.

Mars is easily identifiable in the night sky by its prominent red hue. Thanks to the fleet of spacecraft that have studied the planet over the last decades, we know that this red color is due to rusted iron minerals in the dust.

Results from a new study show that the water-rich iron mineral ferrihydrite may be the main pigment behind Mars’ reddish dust.

A study, conducted in part by NASA, indicates why Mars is red — and, more importantly, what this says about potential life on Mars.