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OK, someone educate me. Verdigris vs corrosion

BBNBBN Posts: 3,761 ✭✭✭
What's the difference? If a copper coin sits in the cup holder of my car and gets green crud over a period of 6 months will that be verdigris or corrosion? If it's verdigris, how long would my coin have to float in mineral oil to remove it?

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Comments

  • llafoellafoe Posts: 7,220 ✭✭
    Corrosion is caused by oxidation (one cause)... oxidation of iron is rust... oxidation of copper is verdigris.

    Verdigris is the by-product of corrosion.
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  • BBNBBN Posts: 3,761 ✭✭✭
    Thanks, so what I have on this wheatie is basically verdigris. Would mineral oil and how long? Thanks

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  • the problem with verdigris is that the corrosion that causes it eats into the surface of the coin, so mineral oil or olive oil would probably loosen the verdigris and might disolve it, but you would be left with a pitted wheatie
    Cecil
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  • FrankcoinsFrankcoins Posts: 4,569 ✭✭✭
    Verdigris is a complex chemical mixture of compounds, complexes and water. The primary components are copper salts of acetate, carbonate, chloride, formate, hydroxide and sulfate. The secondary components are other metallic salts, acids (organic and mineral), atmospheric gases and water. All the components are in an ever-changing and extremely sophisticated electrochemical reaction equilibrium that is dependent on the ambient environment.

    (wikipedia)
    Frank Provasek - PCGS Authorized Dealer, Life Member ANA, Member TNA. www.frankcoins.com
  • RWBRWB Posts: 8,082
    This also happens to opera fans who listen to too much Italian opera.
  • TevaTeva Posts: 830
    To me verdigris is active and corrosion is kind of a past tense
    reference to the damage left behind by things like verdigris
    and carbon and organic contamination.
    I may not be correct but thats my perception when talking copper.
    Give the laziest man the toughest job and he will find the easiest way to get it done.
  • AnkurJAnkurJ Posts: 11,366 ✭✭✭✭


    << <i>To me verdigris is active and corrosion is kind of a past tense
    reference to the damage left behind by things like verdigris
    and carbon and organic contamination.
    I may not be correct but thats my perception when talking copper. >>



    Spot on! I agree 100%!
    All coins kept in bank vaults.
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  • llafoellafoe Posts: 7,220 ✭✭


    << <i>To me verdigris is active and corrosion is kind of a past tense
    reference to the damage left behind by things like verdigris
    and carbon and organic contamination.
    I may not be correct but thats my perception when talking copper. >>



    It's just like fat... the lower levels are active (actively being added by McDonalds consumption) and the outer layers are past tense (having already been added by McDonalds). Fat is still fat... whether it's on top or on bottom. Once you remove the source (McDonalds or Oxygen) it will no longer be active.
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  • LanceNewmanOCCLanceNewmanOCC Posts: 19,999 ✭✭✭✭✭
    .
    .


    << <i>This also happens to opera fans who listen to too much Italian opera. >>



    how do I recognize the early stages of this?

    i do have a nice collection of live performance videos in my itunes library

    hopefully all the other trance, country, hip hop, alternative, classic rock will hopefully dissolve any build-up from the IA.
    .
    .

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  • notwilightnotwilight Posts: 12,864 ✭✭✭


    << <i>What would the green tiny clumps that you find on old bust dimes and bust half dimes be called? >>



    I'd say those would be a form of verdigris. Anything green is generally (not always) copper. Early alloys were not always as well mixed as they are today so a copper fleck can corrode.

    Verdigris is generally any of various copper compounds that form on coins. It can be actively corroding the coin or not very actively corroding. Probably never totally dormant. Remember most coins in circulation ae exposed to sweaty fingers, oils, dirt, and various airborne chemicals and water. Copper combines with sulphur in environments that have sulphur in the air to form copper sulphate.

    There is really reliable chemical composition of verdegris because it changes. But water, sulphur and chlorine are accelerators and should be kept away from copper.

    --Jerry
  • BarryBarry Posts: 10,100 ✭✭✭
    I would call any green corrosion verdigris.

    Verdi is the Latin root for green.

    Just think of Giuseppe Verdi which is Italian for Joe Green.
  • rickoricko Posts: 98,724 ✭✭✭✭✭
    As stated, verdigris IS corrosion.... it is a copper based corrosion, but corrosion nonetheless... Cheers, RickO
  • howardshowards Posts: 1,239 ✭✭✭
    Verdigris is the socially acceptable euphemism for corrosion on on ancient coins. image
  • lkeigwinlkeigwin Posts: 16,885 ✭✭✭✭✭


    << <i>Thanks, none of these emearld green bumps or clumps can be seen with the naked eye, one must use strong mag and the TPG's always holder them with these microscopic clumps on the surfaces. I notice them because I put every coin under strong mag to see if it has been messed with in years gone by. >>

    I send all such coins back to PCGS to remove/neutralize the verdigris (or PVC). It's free, except for shipping, and I have never been unhappy with the results.
    Lance.
  • MyqqyMyqqy Posts: 9,777


    << <i>Just think of Giuseppe Verdi which is Italian for Joe Green. >>



    So, how does one say "mean" in italian to go along with Giuseppe Verdi? image
    My style is impetuous, my defense is impregnable !

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