Billion-year-old rocks pulled from deep below the Sahara Desert have revealed the earliest colored molecules found on Earth. They aren't black, brown, or even green. Instead, think pink. Nur Gueneli of Australian National University was examining molecules from crushed rocks discovered a decade ago by an oil company drilling into a marine shale deposit beneath Mauritania's Taoudeni Basin when she extracted a pink pigment. "I heard this screaming in the lab," then Gueneli came running with "this bright pink stuff," fellow researcher Jochen Brocks tells the Guardian. "It turned out to be real pigment, 1.1 billion years old." At least 500 million years older than other biological colors discovered, the pigment came from molecular fossils of chlorophyll, produced by tiny cyanobacteria that lived in ancient oceans, per a release.
Imagine finding "fossilized dinosaur skin that after 100 million years was still iridescent green or blue," says Brocks, whose research was published in PNAS, per ABC Australia. "That's what we found" except the molecules "are 10 times older than a T-Rex would have been." Chlorophyll is generally associated with green organisms, but different subtypes carry different colors, explains Inverse. In this case, the bacteria range from blood red to deep purple, and appear pink when diluted with water. "The cyanobacterial oceans started to vanish about 650 million years ago, when algae (much bigger than cyanobacteria) began to rapidly spread to provide the burst of energy needed for the evolution of complex ecosystems, where large animals, including humans, could thrive on Earth," says Brocks. (This is the first new blue in 200 years.)