Lithic means stone and in archaeological terms it is applied to any stone that has been modified in any way whatsoever by humans. Lithic analysis, therefore, is the study of those stones, usually stone tools, using scientific approaches. The branch within archaeology that undertakes the scientific analysis of archaeological materials is called archaeometry.
The work of the lithic analyst or stone tool expert involves measuring the physical properties of the tool and will include categorising the type of tool, listing its characteristics and noting wear and usage marks.
A Multi-Disciplined Science
The analyst must be thoroughly trained in stone tool production techniques to be able to draw valid conclusions about the lithic artefact.
Much information can be gathered from the study of lithic materials. For example, the sources of raw materials to make the tools, can tell how stone was procured and perhaps even the trading patterns of cultures without raw stone. The nature of the materials and the finished products help reveal their technological knowledge, skill base and common learning. Artefacts that can be dated often provide insights to more accurately amend the chronological record.
In order to conduct good research in the alcove of archaeometry, experts must be able to draw on the diversity of many of the earth sciences and allied disciplines.
Techniques for dating lithic tools vary from the simple observation of the known existence of a civilisation at the artefact’s discovery level, through to sophisticated thermo luminescence methods. Radiocarbon dating is widely applied to tools with organic attachments such as wooden handles or rope bindings but C14 methods are not reliable when items have been water saturated.
Location and Procurement
Studies to reveal the source of raw stone materials have been at the head of modern archaeological research. Its importance lies in discovering the extent to which stone tooled people travelled to appropriate their basic implement needs. This may, in turn, permit the re-discovery of new sources of raw materials for use today. Methods used to compare artefacts with geological locations include using x-rays, scanning electron microscopes, thin section sampling and electron analysis.
Wear and Usage
Most stone tools display recognisable evidence of wear and use. This should not be confused with the intentional chipping or breaking applied to the stone in order to make it a tool. For example, a flint knife will have been chipped deliberately along its length to form a cutting edge, but it may also show signs of fine polishing from its continued use. This scrutiny is called microwear analysis. Its potential for identifying past human subsistence and handcraft activity is a valuable window into earlier periods. By elucidation and measuring the occurrence of microwear polish and identifying polishes on different raw materials, the tool expert is helped to create a working picture of the daily lives of former cultures.
Heat Treated Stone
Lithic researchers are always interested in whether stone tools were tempered or shaped purposely by fire. High temperatures can change the structures within stone. Lithic analysis laboratories apply various techniques such as magnetic susceptibility and thermo-remanent magnetism to reveal a rock’s history.
Thermo-remanent magnetism is a measurement system that deals with the remanent magnetism in the magnetic materials found in stone that has been heated to very high temperatures such as in a brick kiln. High heat changes the stone to have a magnetic field directionally more like that of the earth. Upon cooling the magnetic field will become locked. This process is only useful on objects that have not been moved, such as fire hearths or brick ovens.
More precise identification of burning or deliberate thermal treatment of lithic artefacts can be obtained by thermo-luminescence. The primary purpose of this technique is to date the heating incident.
Getting to Know the Old Tool Maker
The archaeometrist has a varied array of techniques suitable for solving the problems of analysing raw stone materials and artefacts. Understanding the interplay between raw material procurement, heat treatment methods and artefact production and use can enhance our understanding of the skills of the forgotten stone worker.