In this paper we looked at how early hominins (tool‐making humans) at the site complex Melka Wakena in the Ethiopian highlands chose different stone materials for making percussive tools (like hammerstones). We gathered stone samples of different rock types found in that area. We measured their physical and engineering properties to see how the raw materials might differ in performance. We found measurable differences in the rock types, harder and denser rocks tended to show less volume loss (for example less damage) under the same experimental stress. For example, one rock (glassy ignimbrite) showed very low visible damage at macroscopic scale compared with others. It gives us concrete evidence that early humans weren’t just randomly picking stones; they may have been making informed decisions about which rocks to use for tools based on their likely durability and suitability for the task. This adds to our understanding of cognitive and technological behaviours in deep prehistory. Also, by establishing a baseline of raw material properties, we can later compare actual archaeological tools and see how performance and raw material choice relate.