Experts discovered that some of the silcrete stone tools created in South Africa during Middle Stone Age were crafted with controlled use of fire at the early stage of production.

A recent study by Anne Delagnes (University of Bordeaux) and colleagues showed that silcrete rocks were subjected to heat treatment 70000 years ago to modify the rock properties to make creating tools or blades easier. The tools were found at Klipdrift Shelter, a recently discovered Middle Stone Age site located on the southern Cape of South Africa. Archaeologists conclude that heat treatment of the stone tools from the site may provide the first direct evidence of the intentional and extensive use of fire applied to a whole  chain of stone tool production. The discovery was made using a novel non-destructive approach to analyse the heating technique used in the production of silcrete artefacts.  This analysis revealed heat treatment of over 90% of the silcrete, highlighting the important role this played in blade production.

This intentional heat treatment was a major asset for Middle Stone Age humans in southern Africa, and has at present no known contemporaneous equivalent elsewhere.

(after Popular Archaeology)