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 Replies: 24 / Views: 3,405 |
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Pillar of the Community
United States
5838 Posts |
In a previous post I discussed finding a few Lincoln cents from the 1930s that were still shiny and red, and the consensus was that they must have been recently pulled from a collection in order to still be red after all that time.
I was just looking through my pocket change and found one from 1984 that was also shiny and red and was wondering if that was at all unusual. I mean, I have cents from 10 years ago that are already turning brown, so would a 30-year-old cent need to have been specially protected in order to remain red, or is it common to find them in that condition today?
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CCF Sponsor
United States
702 Posts |
It depends entirely on what it has been exposed to. Oils from hands, air quality, and water effect the4 patina, just as any metal that tarnishes. If a coin has been living packed inside a roll with no exposure to any elements or circulating air, there's no reason it can't remain mint red for many many years. On the other hand, a 2012 D that is sitting on a window ledge by the sea that gets picked up and used will be turning already.
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CCF Sponsor
United States
702 Posts |
It would be fun if biokemist (is that his name?) could give us a full explanation of how and why Lincolns and other coins tone!
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Pillar of the Community
 United States
5838 Posts |
All right, thanks. I guess I'm just really asking whether anybody would consider it unusual to find a circulated Lincoln Cent from 1984 in mint red condition... |
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Pillar of the Community
United States
1436 Posts |
I sure it was either in a mint set that was broken up, or possibly from a roll
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Bedrock of the Community
Australia
21786 Posts |
It is my guesstimate that a cent in continuous circulation would loose all of it's mint lustre in about 5 years.
A freshly minted cent sprayed with clear acrylic lacquer should retain that lustre indefinitely.
I did that with a '64 half dollar in 1964, for fun. It is as fresh as the day I treated it.
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Pillar of the Community
United States
1116 Posts |
Sel I didn't know that spray acrylic would keep its sheen that long. Over 50 years is quite a milestone. When I have used the stuff on my projects I usually ends up having to be refreshed within a few years. Of course thou maybe it's because I spray it on wood which is a lot more porous that metal. But, I'm hoping that the brass cane handle that I sprayed it on stands up that well for me.
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Bedrock of the Community
Australia
21786 Posts |
ghostrider:
The sprayed '64 Half that I have has always been in a Mylar 2x2, but that has been in a PVC album page for all of it's life.
Perhaps the lacquer has not degraded, because it has not been subject to wear or natural oils from the skin. I guess that the imporosity of the coin's surface may have helped it as well.
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Pillar of the Community
United States
543 Posts |
I could be wrong, but I feel that any 1980s zinc cents that have retained their luster over the decades have done so because they have spent most of their lives in a coin jar or a couch.
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Pillar of the Community
United States
1795 Posts |
Well its what the coin has been exposed to; but many have been taken out of collections, coin jars etc. Who knows the reason or why just be grateful that as a collector you have liberated it from circulation for your collection. I'm always happy to find coins that have that mint look or luster that we all so desire.
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Valued Member
United States
232 Posts |
Searching through rolls of coins it is not that uncommon to find cents that are 20+ years old that are still red. I don't know if that just means it has not circulated much, but they are not that hard to find if you are on the look out for them (and look through a bunch of rolls).
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Pillar of the Community
United States
613 Posts |
I find 80s coins all the time in a red state. My assumption has always been that that particular coin is only seeing it 2nd, third or fourth use in its life after having spent the majority of the past thirty years in a jar or otherwise in storage.
Anyone: when retail banks get loads of pennies, do they very quickly circulate back out? Is there anywhere where mixed pennies coming in from the public wind up warehoused for a few years before they go back out?
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Pillar of the Community
United States
1436 Posts |
Coins tone at different rates based on the 3 "H"s... heat (temperature), humidity & handling. I had some coins that were put on a shelf in our spare bathroom that toned VERY quickly. If they're not exposed to the 3 "H"s, they will tone at a much slower rate
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CCF Sponsor
United States
702 Posts |
I find mint red coins from up to a couple of decades ago in circulation with some regularity. They're not always nice, but they're out there. I found a couple of '64s the other day walking around Pasadena. Somebody had recently stepped on them, but they were beautiful mint red.
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Bedrock of the Community
United States
20753 Posts |
Quote:
Coins tone at different rates based on the 3 "H"s... heat (temperature), humidity & handling. I had some coins that were put on a shelf in our spare bathroom that toned VERY quickly. If they're not exposed to the 3 "H"s, they will tone at a much slower rate Almost. However although temperatures do effect the rate of chemical reactions, there are other factors that are more important. When Copper is exposed to moist air it first becomes coated with a thin layer of Cuprous Oxide (Cu2O) which appears sort of a brownish tint. With additional Oxigen and moisture, this process continues to darken the Copper. If a dull greenish appearance occurs, it is usually due to the presence of more moisture (H OH) and Carbon Dioxide (CO2). (H OH) although most say H2O is in reality Hydrogen Hydroxide or water. If there is suffiecient Carbon Dioxide, moisture in the invironment, it will react with the Cuprous Oxide on the Copper Coins to produce [CuCO3-Cu(OH)2] otherwise noted as Copper Carbonate. The so called handling has little to do with toning. Handling of a coin usually puts oils and acids from a person's body on a coin. Oxygen is our main culprit. |
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Bedrock of the Community
Australia
21786 Posts |
[CuCO3-Cu(OH)2] is a double salt of copper and is AKA copper hydroxycarbonate, AKA verdigris.
A thin even layer on an ancient bronze coin can enhance the value, but when
it is occurs in pits in the surface, 'copper disease' is the cause, and some serious chemistry is required to prevent further damage.
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Replies: 24 / Views: 3,405 |
Posted 12/07/2012 12:46 pm
