Stone Tools in the Lab

Once excavated, artefacts are carefully air-dried and wrapped to avoid being touched. Similarly, when they are delivered to the lab, gloves are worn, so that the artefacts remain untouched and uncontaminated. A series of procedures are then followed…

The following methods are applied to stone tools in a lab environment to extract evidence that addresses the following questions about the artefacts:

• What were they used for?
• What did they come into contact with?

1. Photography

Photographs and careful documentation of observations of the artefact in its raw form are captured. The artefact is removed, the surrounding sediments are photographed, and the artefact is photographed from every angle.

2. Taking samples

Samples are extracted from the surface of the artefact and the surrounding sediments for analysis of organic molecules (e.g. lipids) and the chemical composition of the sediments.

3. Microscopy and washing of artefact

The artefact is viewed (before and after washing) under low-powered magnification to identify obvious roots, damage, scarring features etc. It is then viewed under higher magnification to identify the orientation of scratch marks or striations, the nature and angle of scars, polish from use, and the amount of rounding of the use-wear traces.

4. Spectroscopy

An artefact may then be passed on for further analysis using ‘vibrational spectroscopy’ (Raman and FTIR), which is a technique that uses scattered and reflected light to identify the chemical composition of particles (e.g. proteins, lipids, carbohydrates).

5. Analysis of cleaned surfaces of washed artefacts

After microscopy and spectroscopy observations, documentation of the artefact’s polished surfaces takes place to add further insights to the past use of the artefact.

Conversation starter

• Why is it important that the artefact remains untouched?

• Why is it important to consider the sediments with which the artefact has come into contact?