Yeah, well...what everyone else said LOL. Honestly, tho? I used to find a lot of rocks that I figured were- or might have been- used for something or other. I called them 'tools of convenience'. As such, they are impossible to assign as an artifact, so therefore NOT an artifact. The problem is that if you can't prove a specific use through design or wear, you can't call it an artifact. They may or may not have been used- ever- as a tool, but that will remain a mystery.