Cores and Flakes

Stone-flaking involves striking pieces off a rock. The pieces are called ‘flakes’, and the rock is called a ‘core’. At the most basic level, all stone tools are either cores or flakes. The history of stone technology tracks how humans have refined their stone-flaking techniques to make the specific cores and flakes they needed for tools.

Cores and flakes were first produced in the Lomekwian period in Kenya, about 3.3 million years ago, but systematic and well-controlled stone-flaking was not in place until the Oldowan period in Ethiopia, about 2.6 million years ago. Simple cores and flakes persisted right up until the present day, with more elaborate stone-flaking technologies appended onto this simple foundation.

Reducing a core can involve strategic planning, by striking off flakes in a certain way in anticipation of how you want the core to look many flake-removals into the future. For example, Levallois cores, made early in the evolution of our species, are an example of core reduction that required strategic planning. But simple core reduction can be done without strategic planning, by only worrying about the immediate flake removal, and adjusting to the effects of removing that flake when striking off the next one. This can be done without planning ahead, and the approach is sometimes called ‘least effort’ flaking.

The most common technique of least-effort flaking is using a hammerstone to strike flakes from a core. Removing one flake creates suitable surfaces for removing the next flake. When the core is flipped and rotated between these platform surfaces as the core is flaked, different types of cores are produced. For instance, bifacial core is created by striking flakes from two surfaces along one edge, a single-platform core is created by striking flakes in the same direction from one platform surface, and a multiplatform core is created by flaking from two or more of platform surfaces.

The flakes struck from a core were exceptionally useful as hand-held cutting and scraping tools, and most least-effort stone flaking was probably done to produce flakes for tools. Flakes were typically used unmodified while held in the hand, but occasionally they were put in simple handles. In Australia, resin was sometimes added to the back edge of a flake to protect the hand. A flake is sharpest when it is struck from a core, but sometimes a dull edge was flaked, or ‘retouched’, to rejuvenate it.

Cores from flake-making were often discarded after useful flakes were struck from them, but large cores sometimes served as heavy-duty tools. In some cases, the core was made deliberately for use as a ‘core tool’, with the flakes discarded as byproducts in making it.

Bipolar flaking is another common way that cores were reduced. In bipolar flaking, the core is braced on a hard surface such as another stone, and a blow is struck onto the core, splitting it into sharp-edged flakes and fragments. The technique is similar to using a hammer to crack a nut. Bipolar flaking was done by the earliest hominins millions of years ago, and it was still done in the recent past in New Guinea and Australia.