Canberra - Scientists believe they have discovered the oldest colours in the world - and they are bright pink.
Researchers discovered the pigments, produced by ancient microscopic cyanobacteria, after extracting 1.1 billion-year-old rocks found in marine black shale deep beneath the Sahara desert in Mauritania, according to the study published in science journal PNAS.
The scientists said the pigments were the "oldest biological colour" and was more than half a billion years older than previous pigment discoveries.
"The bright pink pigments are the molecular fossils of chlorophyll that were produced by ancient photosynthetic organisms inhabiting an ancient ocean that has long since vanished," said Nur Gueneli, a scientist from Australian National University who found the molecules as part of her PhD studies.
The researchers crushed the billion-year-old rocks to powder, before extracting and analysing molecules of ancient organisms from them.
The fossils range from blood red to deep purple in their concentrated form, and bright pink when diluted, according to the scientists.
"The precise analysis of the ancient pigments confirmed that tiny cyanobacteria dominated the base of the food chain in the oceans a billion years ago, which helps to explain why animals did not exist at the time," Gueneli said.
The rocks had been sent to the university from an oil company looking for oil in the Sahara desert about 10 years ago.