For the Rainbow Warriors

[stevo1962]

A recent grading result with some nice colours

[nealeffendi]

DROOL!! Love toning on coins and your penny has just about the nicest colouring there is.

[JeffH]

Beautiful colouration. No green -probably just as well.
What is the grade on that one?

[trout]

https://www.pcgs.com/cert/85761098

Very Nice coin :good:

[stevo1962]

Beautiful colouration. No green -probably just as well.
What is the grade on that one?

PR65BN

[ausjack]

Sure is a beauty Stevo :good: Lucky PCGS is looking at our purple coins better now than they did a few years ago :winkextra:

[kchan1111]

woow!

[Goldseeker]

That must be one of the most beautiful coins I have ever seen.

Would look good in my collection.   Address follows.......!

[Hercules]

Please pardon my ignorance, but why do pre-decimal copper coins (like the penny and halfpenny) develop that beautiful rainbow toning, but not decimal ones (like the 1c and 2c)? Does the rainbow toning come from exposure to air or from something else? :dontknow:

[trout]

Please pardon my ignorance, but why do pre-decimal copper coins (like the penny and halfpenny) develop that beautiful rainbow toning, but not decimal ones (like the 1c and 2c)? Does the rainbow toning come from exposure to air or from something else? :dontknow:

The 1&2 cent coins DO get the Purple/rainbow tones But they are usually uncirculated and proof coins.
I have a few here and will take some images tomorrow :ok:

[gabby]

Very nice indeed stevo

Would love a few like that

[Cockatoo Coins]

Quickest way to get rainbow toning on a copper like this is to expose it to large amounts of PVC then remove it. Gives you all kinds of wild colours, not really a good thing for your coins though. Pretty common on alot of the early proofs to some degree

[Hercules]

If the rainbow toning is a form of PVC damage, then why is PCGS grading it? I thought they had a policy against this sort of thing. Does PCGS treat rainbow toning differently to green toning, and if so, why? Apologies for my ignorance. :dontknow:

[autocoupler]

Often thought about this myself. Without knowing the answer, my gut tells me that "green" is a disease, and "rainbow toning" is a result of contaminating gasses.

[Cockatoo Coins]

The PVC residue has been removed in this case so no longer poses the issue of causing further damage to the coin while in the holder which is what PCGS is afraid of. The reason why they still grade them is because the coins surfaces are still intact, the PVC didn't have enough time to corrode into the surface. The chemicals either in the PVC or the ones used to remove the PVC have likely caused the colouration as they have reacted with the copper in the penny. Often with extremes in colouration PCGS will still give them a questionable colour but looking at Steve's pictures of this coin elsewhere the colours don't seem as vibrant in the flesh so the graders obviously felt this was within their standards also hence the grade.
This differs from green Verdigris as verdigris has the ability to cause considerable further damage to the coin in a slab, unless adequately treated often it can cause irreparable damage in a matter of months not the years PVC usually takes.
Both have thresholds with PCGS as to what they will accept and what will get a details, the main factors to consider is whether the surfaces are damaged and whether the corrosive element is active.