Early humans living in southern Africa in the Middle Stone Age after 65,000 years ago used advanced heating techniques to produce silcrete blades, according to a new study. This image shows heated silcrete artifacts made by Middle Stone Age humans at Klipdrift Shelter, South Africa. Image credit: Katja Douze / University of the Witwatersrand. South African Middle Stone Age humans deliberately heated silcrete, a hard, fine-grained, local rock, so that...
