What is the green stuff on this coin?

Discussion in 'Coin Chat' started by Insider, Nov 3, 2016.

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  1. Insider

    Insider Talent on loan from...

    Here is the same stuff on a large cent. Bottom photo is the start of removing it.
     

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    Insider, Nov 3, 2016
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  3. Markus1959

    Markus1959 Well-Known Member

    Be careful my friend - she is a Godsend to you!!:)
     
    Markus1959, Nov 3, 2016
    #22 + Quote Reply
  4. DysfunctionalVeteran

    DysfunctionalVeteran Oddly enough

    Whats it taste like?

    Sent from my SM-G935P using Tapatalk
     
    DysfunctionalVeteran, Nov 3, 2016
    #23 + Quote Reply
  5. tommyc03

    tommyc03 Senior Member

    Cu CO 3. Cu (OH) 2...Copper Hydroxide & Copper Carbonate. I have no idea what this all means but that's what a Bing search yielded. What happened to physicsfan?
     
    tommyc03, Nov 3, 2016
    #24 + Quote Reply
  6. Smojo

    Smojo dreamliner

    Either way its copper base so I'd say verdigris. I've had it were it comes off easy with a toothpick & had it so bad acetone wouldn't touch it. Just saying.
     
    Smojo, Nov 3, 2016
    #25 + Quote Reply
  7. GDJMSP

    GDJMSP Numismatist Moderator

    I've seen verdigris on many different coins with many different looks. It can be hard and crusty, soft and powdery, flaky, even soft and fuzzy looking like in a couple of these pictures. And I've seen in on more copper pipes and fittings that I can count - with all of those same looks.

    And the only thing I've ever been able to determine is that verdigris goes through different stages, depending on conditions and how long it's been forming.

    But if you want to know for sure what it is, scrape off a little and take it to a lab and get it analyzed. But I'll bet ya dollars to donuts they tell it's verdigris.
     
    GDJMSP, Nov 4, 2016
    #26 + Quote Reply
  8. Insider

    Insider Talent on loan from...

    I think that's what we all call it but I'm curious about the conditions it forms under, chemical composition, why it corrodes some coins and not others. Notice there are a lot of chemists here. :sorry::shame: I'm trying to get "spoon-fed" answers rather than taking a look on the net for myself - back burner stuff.
     
    Insider, Nov 4, 2016
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  9. BadThad

    BadThad Calibrated for Lincolns

    It's verdigris, not sure why all the mystery. You have a coin with copper in it, if exposed to air/water, verdigris will form. As Doug mentioned, verdigris is a complicated beast. There are many variables in the composition with one thing in common - copper. I wrote this for Wiki:

     
    BadThad, Nov 4, 2016
    #28 + Quote Reply
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