The importance of understanding the influence of raw material on fracture mechanics when searching for projectiles

The results of an elaborate experimental program on projectiles indicate that raw material is among the key variables affecting the fracture mechanical behaviour of a lithic armature on impact. This aspect has been underestimated in earlier projectile studies, where results have either been directly compared to previously published experimental data irrespective of raw material differences, meaning that raw material has been considered an irrelevant parameter, or experimental replicas have been made of materials that closely resemble their archaeological counterparts. Considering the variability in lithic resources in Africa, projectile studies focused there should rely on a clear understanding of the effect of raw material on fracture formation. We conducted a pilot experiment with a universal testing machine to examine how different raw materials react to standard mechanical stress. This communication presents the results of the experiment and puts them in the context of experience gained from our previous work.