1969-S Quarter with frosting Error

Discussion in 'Error Coins' started by Pete Apple, Sep 16, 2019.

  1. Pete Apple

    Pete Apple Active Member

    Previously, I had reported that this Quarter appeared to be a Doctored Coin. It turns out that it is not doctored, but is, in fact, an Error – and an apparently rare error at that. I sent the Quarter to Mike Diamond. Here are his comments:

    Prior to me sending the coin to him and commenting on the photos only, he said: “It's unlikely to be a case of frosting slopover because, as far as I'm aware, intentional frosting of proof coins wasn't introduced until 1971. Before then, all "frosting" was the result of an early strike (the real cameo appearance).”

    After examining the coin, he said: “The patch of frosting below Washington's queue represents an area of the die face that was missed during polishing. As I mentioned before, the frosting is not enhanced during this time period to make every proof a cameo. I abhor the introduction of that step in 1971, as it eradicates the fine details of the design. The much finer frosting seen on your coin is the result of an acid bath (actually, a nitric acid/alcohol solution) that the dies were submerged in prior to polishing.”

    Proof coins minted before 1971 TO 1973 were made using a technique so that only the first hundred coins, or so, had a cameo contrast effect. (In other words the contrast effect itself is rare and the frosting error makes this coin rarer still, I should think).

    The "technique" for the frost on the proofs was that the dies would be hardened and then cleaned of oxides in a mild acid bath. The acid bath would also very lightly etch the surfaces. Then the fields would be polished to the mirror finish. The devices were not polished and no further treatment was given to them to strengthen the "frost". So the cameo contrast came solely from that light acid bath etching. That light etching did not survive long once the dies were put into use. The deep cameos were simply the result of a slightly stronger etching.


    Still1307.1.jpg IMG_6457.1.JPG IMG_6461.1.JPG
     
    Azariana, Stevearino, TyCobb and 7 others like this.
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  3. paddyman98

    paddyman98 Let me burst your bubble! Supporter

    Now that is new and interesting.
     
  4. Raizac

    Raizac Active Member

    i second that!!!!! wow cool
     
    Pete Apple likes this.
  5. TyCobb

    TyCobb A product of PMD

    That's so neat. Very nice, sir.
     
    Pete Apple likes this.
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