Breaking up a silcrete boulder with hammerstones

The ‘Stone Flaking Techniques’ video series by the Museum of Stone Tools demonstrate some of the flaking techniques that were used to make tools from the origins of the technology, ca. 3.3 million years ago, to the recent past. The techniques are demonstrated by Professor Mark Moore, Museum Director and archaeologist at the University of New England in Australia. This video shows how large hammerstones were used in prehistory to make very large flake blanks. The stone is a silcrete (orthoquartzite) boulder from western New South Wales, Australia. The goal was to make thick pieces of stone to serve as blanks for tools. Large flake blanks like the ones made in the video were made into bifacial handaxes by our hominin ancestors some 1.5 million years ago, and they served as blanks for tools from that distant past right up to recent times. In Australia, large flakes were made and trimmed at the stone quarries, then carried away to serve as chopping tools and as sources for smaller flakes to use and knives and scrapers. Dr Moore manipulates the core so that the platform surface is facing him. The core is rested on the ground until the very end, when it becomes light enough to comfortably lift. Many of the propagating cracks stalled when they encountered soft cortex at the outside of the boulder, and needed to be carefully tapped until they detached. At one point Dr Moore was unaware that a prior blow had initiated the flake but it was still stuck to the core at the cortical end. When he strikes the core again the flake is split into several large fragments. Hard hammer percussion like this can be dangerous when flakes pop off the hammerstone, as they sometimes fly up towards the stoneworker's face. Hammerstone spalls are detached twice during this video, but, luckily, both times the flakes were propelled away from Dr Moore. This kind of heavy percussion causes a great deal of attrition to hammerstones.