Scientists identify bright pink as the world's oldest colour

Biogeochemistry Lab Manager Janet Hope holds a vial of the oldest pigment in the world. Photo / ANU

The world's oldest colour is not some dull grey or just any shade of dirt brown. It is actually bright pink.

Pigments of the world's oldest biological colour have been found after scientists crushed 1.1billion-year-old rocks from a marine shale deposit under the Sahara desert in Mauritania.

"Of course you might say that everything has some colour," senior lead researcher, Associate Prof Jochen Brocks from the Australian National University, told the Guardian. "What we've found is the oldest biological colour."

The colour pigments found are so old they pre-date animals.

They were discovered by Nur Gueneli, a Phd student who crushed the rocks and then analysed the molecules from the rock powder.

These pigments are more than half a billion years older than the previous known ones.

"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," she said in a statement.

The research was led by the Australian National University (ANU) and supported by Geoscience Australia.

The university received the rocks from an oil company that was looking for oil in the Sahara desert about a decade ago.

The discovery is a major breakthrough in the study of how animals came to exist and why they came along so late (the Earth is about 4.6 billion years old, yet the first creatures only appeared around 600 million years ago).

Researchers analysed the pink molecule and found it was produced by tiny cyanobacteria.

"They had been at the bottom of the food chain. In the modern ocean we have algae at the bottom of the food chain. Microscopic algae are still very small but they are still 1,000 times bigger than cyanobacteria," Associate Professor Jochen Brocks said.