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Diamond Help

  1. Oct 24, 2007 #1
    Hey guys, I'm doing a project on the physical properties and :. uses of diamond. I've got this week to research, and next week I have to create my presentation. I've been looking up all the uses/properties of diamond.

    I know that:
    diamond is the hardest natural element
    this means that diamond can't be scratched by any other natural element apart from itself.
    And this is why they use diamonds to cut other diamonds when creating "brilliant diamond stones".

    However, this confuses me:
    I understand the process of how the diamond blade works, but surely, if diamond is so hard, why does it get worn down?


    I am also curious to how Diamond polishing paste works? surely a slurry of suspended diamond particles would scratch the surface, as opposed to polish it, due to its hardness.


    Many Thanks in advance for any help I receive!
  2. jcsd
  3. Oct 24, 2007 #2


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    Diamond is hard but not inifnitely hard so it still gets eroded by other materials. The stainless steel of a knife blade is harder than a tomato but will get blunt if you cut enough of them.
    Diamond cutting wheels only have a thin layer of diamond dust on them, it's more a case of the dust being worn off the wheel as nuch as individual diamond crystals being destroyed.

    Polishing a surface is the same as scratching it - just with smaller, uniformly distributed scratches.
  4. Oct 24, 2007 #3
    thank you very much mgb_phys! :)
  5. Oct 24, 2007 #4
    Think of it this way. Suppose you hit the tip of a diamond with a hammer. It will probably hurt the hammer, but it will also hurt the tip of the diamond. Think of this, if you carve a spear from wood with a pocket knife, you will notice that if you try to stab things with it, the tip fold in easily.

    The diamond blade is similar to this. The very edge of a blade is fragile. Take a steel knife. If you cut enough potatos with it, eventually the blade will wear down. No matter how hard something is, when it exerts a force on something, that thing will exert the same force back on the edge, and a force exerted on the edge will always take a tiny bit from that edge.

    I hope I helped you understand that part about the diamond blade.
  6. Oct 24, 2007 #5

    Doc Al

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    Staff: Mentor

    I suggest you also do some research on the index of refraction of diamonds and how that contributes to their sparkle.
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