Not always, but it's one of the common indicators. The general process for survey identification goes like this: you walk around looking at the ground and notic

Not always, but it's one of the common indicators. The general process for survey identification goes like this: you walk around looking at the ground and notice the unnatural ones. This is a purely intuitive sense, so you pick one up and look closer to see that yep straight edges, conchoidal fractures, common material, found in a bed with other clear lithics, etc. Bag and tag.