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How to determine impact fracture?

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  • How to determine impact fracture?

    I did a bit of research online but it's all still a bit foggy to me. What are some of the tell tale signs of an impact fracture versus something that was just broken in the ground, river, creek, whatever?

  • #2
    Well, a point can break at the tip in more then one way. But, clearly the easiest fashion, that would allow one to tell it was from an impact to the tip, is to see a flake driven backwards toward the base, sometimes ending in a hinge fracture, like a flute driven backwards from the tip. Anyway, here is one that was handy to photograph. Found on a beach. On the one side, you can see the break is driven backwards from the tip. This is what you would expect to see when the point broke from an impact to the tip.

    Rhode Island


    • #3
      Check out this thread, has some good examples...
      Josh (Ky/Tn collector)


      • #4
        Thanks for the replies. I actually did check out that thread before posting and you're right... some good examples. That is the only tell tale sign I can recognize, when the break peels off a flake in a sense, or peels away part of it. I was reading another site and many examples looked just like clean breaks to me... so how could they tell it was an impact fracture?
        Last edited by filmiracl; 05-29-2017, 08:40 PM.


        • Kyflintguy
          Kyflintguy commented
          Editing a comment
          Sometimes there are enough clues to make that kind of assumption I guess. Often you can study a broken piece (especially if you have both halves) and get a good idea of what type of forces contributed to the fracture. Im sure its not fool proof though. I generally just look for the burin type fractures and bending type fractures when trying to identify impacts but Im sure if you know what to look for you could identify many more signs of impact fractures beyond those two common ones I mentioned. Good link!

      • #5
        Very nice learning thread . Thanks for sharing . I do have one where the entire side is impact . Saw it in a book but really like the back up pics .