Chipped stone artifacts can only be made from a relatively small proportion of all available stone types. Only stone that has uniform or homogenous texture, and has very small or microscopic grain size, and is very hard and brittle can be made into chipped stone tools. These qualities of stone allow the toolmaker or ‘knapper’ to break the stone in a controlled and deliberate manner to shape it. Common stone types used for making lithic artifacts include obsidian, flint, chert, and quartz.
Chipped stone artifacts can be characterized as either ‘objective pieces’ or ‘detached pieces’. Objective pieces are those items that have been cracked, flaked, or modified in some way, and may include rock cobbles, broken pieces of stone, or more formalized cores. Detached pieces are those items that have been removed from objective pieces during the modification process. Detached pieces are referred to as blades, flakes, chips, spalls, or debris.
Detached pieces are often removed from objective pieces by either percussion or pressure flaking techniques. The removal of a flake or chip by applying pressure to the objective piece without striking is known as ‘pressure flaking’. This is usually done by placing the tip of an antler or sharpened bone on the objective piece and pushing down and in on the point of applied force. The removal of a flake or chip by striking the objective piece with a hammer or percus-sor is known as ‘percussion flaking’. The percussor is often a stone cobble or pebble (‘hammerstone’), but may also be made of bone, antler, or wood. Different amounts of force used to remove detached pieces are recognized as different load applications. The load application and the angle at which the load is applied to the objective piece will determine the shape and size of the detached piece. Percussion flaking generally has a greater load application than pressure flaking.
One of the most common objective pieces is known as a ‘core’. A core is a mass of homogeneous lithic material that has had flakes removed from its surface. Cores come in a variety of sizes and shapes from all different parts of the world and from all different periods of time. The primary purpose of a core is to supply flakes that can then be used as cutting tools or be made into a more formalized tool. Different core technologies were developed and used based upon the needs or the toolmakers, availability of stone, and the techniques of core reduction passed from one toolmaker to another. Figure 1 Illustrates different examples of objective pieces and detached pieces.
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