It was 2011 and researchers were sifting through dirt-encrusted items excavated from an early human site, Blombos Cave in South Africa. Then one of them noticed nine strangely regular lines on a flake of rock. And further analysis would show that this seemingly insignificant stone fragment was potentially of unique importance for understanding the evolution of our species.
The Blombos Cave is set in a cliff face overlooking the Indian Ocean some 185 miles to the east of the South African city of Cape Town. It has been an especially fruitful source of archaeological material relating to early Homo sapiens since its first excavation in 1991. Indeed, early human artifacts that are 100,000 years old have been discovered in the cave.
We know that small bands of early humans used the cave and that they left behind a wide variety of objects. These items include spear heads, beads fashioned from shells, and pieces of bone and ochre with crosshatched patterns cut into them. Other objects found appear to be evidence of an ability to make ocher pigment in liquid form.