© Science/AAASThe abalone shell was found with an ochre-covered grindstone on its lip.
Abalone shells used to mix paint found in South African cave, new study says.

A coating of bright red powder on the insides of a pair of 100,000-year-old abalone shells is evidence of the oldest known art workshop, a new study says.

The powder was found inside two shells in Blombos Cave near Still Bay, South Africa (map). The substance is the dried remains of a primitive form of paint made by combining colorful clay called ochre, crushed seal bones, charcoal, quartzite chips, and a liquid, such as water.

"A round [stone] covered the opening of one of the shells, and underneath it was absolutely bright red," said study leader Christopher Henshilwood, an archaeologist at the University of Bergen in Norway and the University of the Witwatersrand in South Africa.

In addition to the shells, the team also found grindstones, hammerstones, the remains of a small fire pit, and animal bones that were used to transfer small amounts of the paint.

Blombos Cave has been inhabited off and on by humans for at least 140,000 years, but the ochre-paint studio seems to have been active about 100,000 years ago. Prior to the new discovery, the earliest known ochre-making workshop was 60,000 years old, Henshilwood said.

(See "Oldest American Art Found on Mammoth Bone.")

© Science/AAASThe abalone shell, after it was removed for analysis.
Studio Reveals Chemistry Know-How

The discovery is also proof that early humans were capable of long-term planning and had at least a rudimentary knowledge of chemistry, according to the study authors.

"They seemed to know that seal bone is really rich in oil and fat, which is a critical component in making a paint-like substance," Henshilwood said.

"They also knew to add charcoal to the mixture to bind and stabilize it, and a little bit of fluid, which could have been water or seawater or urine."

While relatively few ingredients were used in the ancient paint, each item had to be individually prepared before everything could be combined inside the shells. For example, the ochre pieces had to be crushed and ground into a powder, the bones had to be heated to release their oils and then crushed, and wood had to be burned to create charcoal.

"The mixture was very gently stirred, and you can see the traces of the stirring [done by fingers] on the bottom surface of the abalone shell," Henshilwood said.

It's not clear what the ochre paint was later used for, but Henshilwood said it's easy to imagine early humans using the substance to decorate their bodies or cave walls.

(Learn more about ancient rock art.)

Early Artists Played With Color

The final product would have been a bright-red paint - due to to the iron oxide in the particular ochre used - was and would have been not too thick or too watery.

There is even evidence that the early artists purposely adjusted the color of their pigments.

"In one [of the shells], there was a tiny piece of a yellow mineral called goethite, which may have been added to change the color slightly," Henshilwood said.

The ancient-paint study appears in this week's issue of the journal Science.