How does peripheral toning occur?
Insider2
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Many of us appreciate beautifully toned rainbow colored coins. Toning can occur in several patterns and colors. **THIS POLL IS ONLY CONCERNING COINS where the toning is COMPLETE around the entire rim of the coin. It can be any color or width from a fine line at the rim to a coin completely toned from the rim into the center. How does this peripheral toning occur.
I think the majority answer to this poll will be a starting point for further discussion.
How does peripheral toning occur?
This is a public poll: others will see what you voted for.
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Comments
I see this from an album or paper roll in contact with the edges.
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Hmmm, I know of 2 well known's, album storage(Library of Coins 1 of the best) and old small holder ANACS slabs. I don't like the only option for this being ONLY happen if something is in direct contact with the Coin's edge. The toning induced by the old ANACS slabs is not caused by what it touching the edge...it's caused by the label. And yes...it will progress past the edges over time and tone the whole coin!
My latest Morgan was likely in an album prior to being slabbed:
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So if you put the label into a sealed jar with the coin, do you think the coin will develop peripheral toning? I think not. Good experiment for someone to try.
I was always taught that it was caused by sulfur in the paper of the older albums, but with what I have learned on this and other forums all I know is I know nothing.
I wouldn't be be surprised to see that wild haired dude on Ancient Aliens claiming it was caused by excrement of the aliens mining for gold and silver in the first ice age.
Sulfur will cause it. But the sulfur can be airborne as well as in direct contact from the paper.
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Some of these right, some are wrong, but none are the complete answer 😀
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Don't ask me about the science part! But in all my years of playing with coins the majority of times the coin always seems to start toning from the edge moving inward. I have played with trying to tone coins naturally long enough to see this, whether it be storing in an old album, old manila flip, or just letting it sit out!
Edit to add...and yes, it takes years to get results!
It's a kind of magic.
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Along with old albums and envelopes that were manufactured with sulphur containing materials, I believe a lot of the old slabs, specifically the NGC "soapbox" and ANACS small white holders tone coins as well.
I doubt old versions of these slabs were as inert as they are today. You see a lot of similar peripheral toning on coins in those slabs and they have similar patterns and colors as well. The timeframe works too, a lot of coins became toned in the 90's and 2000's as they spent time in these holders...
PCI Target toning is almost certainly due to a compound in the slab insert.
You also need to remember that time is a factor. There might have been some compound in the paper label, but after some period of time, no more leaches out.
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Your post means nothing. In fact, you didn't even bother to vote. PLEASE, tell us which choices you believe are right or wrong. Thanks.
It can happen through direct contact, close proximity or artificially.
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time is the key and heat
Actually fluctuating heat! Temperature changes + humidity(especially with paper products to release the Sulphur and whatever) do accelerate the process unless you are talking about cooking it!
Heat is a time compressor - see Arrhenius equation.
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That's why I said unless you want to cook it. You will not get natural attractive toning that way.
Why bother to vote if you don't have the correct root cause? But I will play
2, 3, 5, and 6 are all correct answers. None of these is the root cause, however. The root cause is (in the case of silver and some copper) sulfur compounds coming from along the rim. They don't have to originate at the rim. The source can be far or close as long as there is a diffusion limiter at the rim. The important part is that it must be more likely that a sulfur atom contact the edge than make it to the center.
Like everything, concentration and time and temperature are all important factors. Jmlanzaf is correct that Arrhenius shows us we can compress reaction time by increasing temperature. A PCI slab stored at 40C would tone faster than at 10C. Note this isn't because of the silver sulfur reaction rate...
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I think it is the white plastic myself.
Not entirely sure here, but, I have a collection in the 'Whitman Classic' albums.
Albums I have were manufactured in the US, early mid 90's.
A fair number of the coins have the peripheral toning you mention.
When I placed the coins in the album the were 'white', (clad).
The toning was caused by the chemicals in the album page.
Edit to add,
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Why, oh why is the correct answer not a part of your poll?
It could be because of the silver sulfur reaction rate. IT could also be the diffusion rate. The rate constant of a chemical reaction increases with Temperature (Arrhenius equation), so the reaction does speed up with temperature.
All comments reflect the opinion of the author, even when irrefutably accurate.
Agree with both these gentlemen. Sulphur is the main culprit but would not limit it to that. And since the premise was toned colors and patterns, can exclude oxidation, though that can produce pleasing toning.
True, but remember that a lot of real world problems, like silver toning from a label, have multiple steps. The silver/sulfur reaction is quite fast. Most likely rate limiting step is the release of sulfides from the label, either degradation or volatilization. Not sure which is the case here without more investigation.
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Are you just being funny?
I don't claim to be the even close to the knowledgeable folks on CU so please educate us. What is the "correct answer?" Perhaps I can add it to the poll.
NUTS!
Ditto @jmlanzaf I'll reply when I get more time.
PS In the meantime, perhaps one of you knowledgeable chemists can post an example of a peripherally toned RAINBOW coin that happened it a flip (before it was put into one). LOL.
Oh, why Oooo why are you questioning me question you?
(Please don't underestimate your knowledge here. You are without much doubt within the top 50% of the all-time cleverest and smartest foreign members here.
That's a very Lake Woebegon answer in the traditional Norwegian Batchelor Farmer's left-handed compliment mode.
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I’m have no knowledge about this but I can offer anecdotal evidence based on my own coins. I have several of the old (1970’s) blue Whitman albums with the slides. Over 30+ years many uncirculated modern silver coins developed rainbow toning. It seems that we see rainbows more often on the obverse and that’s true on mine too. My non-scientific opinion is that the rainbows result from a combination of sulfur containing paper in direct contact with the rims over time coupled with the availability of air. We typically press coins in the albums from the front and, at least in my case, that results in more space for air between the slide and the coin’s surface on the obverse than on the reverse. When I look at mine, they are all pressed into the hole so that the back is much closer to its slide than the front. So, I think that at proper temps album paper in direct contact with the coins edge allows sulfur to slowly leach onto the coin where it reacts with the surrounding available air to produce the toning.
Then again, I may be completely wrong because I know I’m scientifically clueless about this.
I would guess that the reverse is toned more darkly?
All comments reflect the opinion of the author, even when irrefutably accurate.
The reverse typically has very little toning.
The original way was usually in folders, albums, and sometimes 2x2 envelopes for years and years.
Imagine an old album, slowly filled, stored through the seasons on a bookshelf or in a drawer, the slides opened every few months, the mom cooking, the dad smoking, and all the atoms sloowly seep from the album, and drift and settle and build up and form an incline like light snow on a windshield, thicker at the rims and thinning out towards the centers...
Nowadays it it takes less time if they do it reasonably well.
Can be done poorly overnight, using liver of sulfer applied to the hole with a q tip and baked at low temperatures for a couple of hours.
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Went with proximity, as I seem to recall that PCI ASE's were toned by sulfur in the label, not the plastic holding the coin. Maybe just a brain poot.
And THAT'S the correct answer!
Is it sulfur, or other related acidic environment and proximity to typically acidic paper product holders? There may be a different atmosphere if coins are in the fancy Whitman holders with the flat plastic sliders that hold the coins, vs the kind smashed into the one sided Whitman's over time.
Some of my 50 year old coins that have travelled with me all around the World in every environment have toning on edges, and some do not, even in the same holders, just different dates.
It is magic, and the Queen video was a nice distraction while reading more ideas.
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We're all just guessing, but I think toning like this came from an album...
And toning like this came from an envelope...
These took many years. Or maybe overnight.
Lance.
Why do you always have to insult people? You add a lot of knowledge to these forums but sometimes the way you go about doing it puts people off. If you want more dialogue then create a less confrontational approach and you might get better results.
Just my 2¢ piece...
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All comments reflect the opinion of the author, even when irrefutably accurate.
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LOL! How high can a nose reach to the sky?
Peripherally
@chesterb asked: "Why do you always have to insult people? You add a lot of knowledge to these forums but sometimes the way you go about doing it puts people off. If you want more dialogue then create a less confrontational approach and you might get better results. Just my 2¢ piece..."
Because I grew up at a time without "snowflakes," political correctness, cry babies, coddling, etc. It is in my nature to be an abrasive little roach with some folks based on the circumstances of our interaction. Fortunately, some folks get through to find I'm a nice person underneath the exoskeleton.
Anyway, when I got the alert that someone posted,I was hoping you had posted an example of a **peripherally toned RAINBOW coin that happened in a flip (before it was put into one). LOL.
PS For your information (as until now just an involved participant in the discussion) I did not insult anyone. I just disagreed with their post
in a big way.
and asked for an example.
I think we can conclude from this poll that peripheral toning virtually ALWAYS occurs when something is in touch with or in close proximity to the entire circumference of the coins edge.
Next question. Can this be artificially induced? New Poll.
Even some people can be artificially induced.
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Alcohol is a good inducer.
I’ll never say never but I think it would be difficult to artificially reproduce a true rainbow effect without leaving evidence of that. However, since rainbow toning occurs as a natural chemical reaction over time, I suppose it is possible to speed up the process. Kind of like a natural diamond versus a man made diamond. The reproductions are always improving and it’s harder to tell now than many years ago.
i feel the answers are inadequate, and multiple answers are correct. That said, it's an area I do not have experience with.
From a strictly statistical perspective, toning occurs in random patterns all the time - for [a reason - we can abstract that away]. So, if it happens on a coin in all different ways, by making it peripheral, you're either witnessing a very low probability event of randomness taking shape/occurring on the edges, or it's been caused by something, on purpose or not (like the old albums). I admit, it is MUCH higher probability of the latter than the former.
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I agree, and so are the dangers of group think.
I have seen modern eagles that are obviously terribly artificially toned, but to do that blow torch effect effect so it looks 30 years old and original, that is another story.
100 year old coins like Morgan's just "look" right when original, and real natural toning is usually the most amazing.
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