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Strange wear and classification question

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  • tomf
    replied
    Wildfire damaged this point, I think.

    It's only bubbled on one side.

    Must have been a hot one though.

    Leave a comment:


  • tomf
    replied
    Mystery solved, I think.

    It's fire damage.

    Excerpt from paper named 'Fire Effects on Flaked Stone, Ground Stone, and Other Stone Artifacts'

    "Obsidian is thermally affected at varying temperatures and at differing lengths of exposure to heat. In field and lab fire experiments, obsidian has been reported to fracture, crack, craze, potlid, exfoliate, shatter, oxidize, pit, bubble, bloat, melt, become smudged, discolored, covered with residue, or rendered essentially unrecognizable"

    Good read.

    https://www.fs.fed.us/rm/pubs/rmrs_g..._3_097_111.pdf

    Leave a comment:


  • tomf
    replied
    Perhaps, they are bubbles that were concealed in the material and then were exposed through wear.

    I think they would be disqualifying, if apparent, when the maker was choosing material.

    Leave a comment:


  • tomf
    replied
    Here's a close up.

    Click image for larger version

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    Leave a comment:


  • tomf
    replied
    Originally posted by Kentucky point View Post
    That is the darn kookiest piece I've seen. Maybe the marks came from hitting other rocks? Definitely unique.
    Kind of looks like gouging but, as you know, obsidian is basically glass and I've never seen glass respond to impacts that way.

    It almost looks like acid corrosion...

    Leave a comment:


  • tomf
    commented on 's reply
    'vesicles' being the correct term, is new word for me. thanks.

  • Kentucky point
    replied
    That is the darn kookiest piece I've seen. Maybe the marks came from hitting other rocks? Definitely unique.

    Leave a comment:


  • CMD
    commented on 's reply
    Fooled me as well. The vesicles had me thinking slag.

  • tomf
    commented on 's reply
    Definitely obsidian.

    Knapped on both faces but heavily water-worn, like south fork says.

    At first I thought it was a scraper but now think it's a point.

    I've got a lot of water-worn obsidian but have never seen this type of pocking before.

    I guess I wondered if anybody else had?

  • south fork
    commented on 's reply
    It's not slag but a water worn piece of obsidian . With a little work on it .

  • 2ndoldman
    replied
    That looks like slag to me. 🤔

    Leave a comment:


  • tomf
    started a topic Strange wear and classification question

    Strange wear and classification question

    I posted this piece as part of a group yesterday.

    I'm intrigued by the unusual wear or pocking on one surface.

    Also not sure if it's a projectile point or what?

    Any thoughts?

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    Click image for larger version

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