This Stillbay point from South Africa dates to ca. 71,000-75,000 BP. The model is made from a plaster cast.
The relatively large Stillbay point in this model appears to have been made primarily by bifacial percussion flaking. Remnants of large invasive scars can be seen on both faces, intruded by shorter shaping scars.
A number of small bifaces emerged in the African archaeological record during the Middle Stone Age, by ca. 235,000 BP. Many of these points were made by non-invasive percussion retouching, but others were fully bifacial tools made by invasive percussion flaking. These various point types were probably armatures for spears although they were likely used for other functions as well. Stillbay points are one of these Middle Stone Age point types. They date to ca. 75,000 years ago at Blombos Cave—a manufacturing centre for Stillbay points—and are found at other similar-aged cave sites in South Africa. Stillbay points are remarkable for the bifacial thinning skills necessary to make them, probably achieved using a soft hammer percussion technique with a soft hammerstone or organic indentor. They also demonstrate the earliest evidence of the pressure flaking technique, where small flakes were removed by pressing a bone against the edge to initiate the flake. It is possible to be exceptionally precise in retouching the edge of a biface using the pressure technique.
Also, Stillbay points demonstrate that flintknappers at the time were systematically heat-treating their stone—primarily silcrete—to make it more amenable to percussion and pressure flaking. Heat-treatment involves slowly raising the temperature of the stone to about 250-350º C without shattering it; at that point, a change occurs in the stone as intermolecular water is driven off. Iron minerals in the stone, if present, change to a red colour, and the stone becomes more glossy. Most importantly, the permanent physical changes that occur at these hot temperatures weakens the stone so that about half the amount of force is necessary to initiate the flake. Although there is evidence that silcrete heat-treatment may have occurred as early as 130,000-200,000 BP in the region, heat-treatment became systematic during the Stillbay period: between about 70% and 90% of Stillbay silcrete artefacts are heat-treated. The controlled and regular use of fire for heat-treatment—combined with the sophisticated pressure flaking technique seen on some Stillbay points—has prompted archaeologists to propose that this is early evidence of the emergence of cognitively modern people like ourselves. Others have proposed that Stillbay points held symbolic value and were items of exchange.