Will red copper eventually be brown ?

Say you had a 1906 Indian cent full red, won't it be brown in another 100 years even slabbed ?

The circa 1800 copper never seems to be available full red. Can any slab prevent it ?

 

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however ... there were no slabs in 1800's

 

Yes, oxygen is needed to brown the copper. Not to say that a coin won't brown in a holder(I'm not sure), but I do believe many coins will remain red indefinitely in a slab. Copper turns brown when it reacts with oxygen, particularly in the presence of sulfur, to form copper oxide.

 

The slabs aren't a vacuum, there's air in there, even if it were 100% airtight. I think they eventually will turn brown unless you could develop a holder that was a vacuum or filled with an inert gas like nitrogen. I won't be around to find out though.

Didn't PCGS or one of the services have to buy some copper coins back because spots developed ? I think the case I'm thinking of was a proof Lincoln, common date, super high grade, silly money item. Something like 5k for a coin from the 60's.

Have any early 80's slabs changed from red to R+B yet ?

 

Yes, I am sure PCGS has bought back coins, as they have developed carbon spots. However, I don't think I have ever seen even an early slab in which a coin graded a red, was brown, let alone red brown. I'd be interested to hear anyone else's input on this, as I really don't know a definitive answer to your question.

 

yes but in the slab the supply of oxygen is rather limited... that might cause a difference

 

You would think that they would offer a service to put an inert gas in the holders and make them air tight. It just seems to make sense to me to offer that, the technology to do it is pretty cheap and the time required wouldnt be all that more. But what do I know

 

Copper preservation is pretty difficult isn't it?

This is the best oldest copper coin that I have at the moment:


Near 220 years copper coin still showing signs of redness

 

NGC is the ONLY grading company right now that has a slab that is air-tight.....I've heard this through another collector so it could be wrong but I think I also saw something about it on NGC's site.

Speedy

 

One of the problems is that over long periods of time (we are talking tens to hundreds of years here) air can migrate through the slab plastic. So it is a question of not only filling with inert gas and getting a truly air-tight seal, but selecting the correct material to construct the slab. And it takes a really long time to test it to see if you got it right!

 

True, but you would think they would offer something so your coins stay shiney your whole life time, I am personally a paranoid person so I store my coins in an airtight box that has a dehumidifier and CO2 pumped in to replace the air, exept for my toning coins which I leave out in random places so they will get vetilation and light for toning.

 

It is obvious that that coin has been cleaned and allowed to re-tone a bit.

Copper and bronze coins are very reactive metals. The only thig that will prevent them from toning is to put them in a perfect vaccum (none exist) and encase them in a completely inert holder (none exist). Any surface contamination will continue to work on the coin even after being slabbed. Carbon spots are fairly common and are caused by drops of spittle or from planchet defects.

Out of all the Indian head cents minted, there are only a few known specimens which are ms67 red. The difference between a ms66RB 1864 and a ms67 red is about $25,000.

 

So does PCGS buy back the 1906 MS-67 Red cent from your grandson 100 years later when it turns brown, and at market price ( if that can even be determined ) ?

Seems it will eventually turn unless that perfect holder is developed.

 

Doug,
As long as they're kept covered with a good plastic away from air circulation,and you keep your mitts off of them,they will stay red beyond your lifetime and maybe your kids.I have a lot of cents in BU that I've kept in Dansco's for years and NO sign of turning brown,including some from the 20's that look like they were minted last week.Even this 97 year old looks like the day I bought it.

 

Are you certain the 1909 gets graded red ? Looks like it could come in R+B.

 

No question that it's RB..I'm just saying it looked the same when I bought it years ago.

 

Did you photograph at the time of purchase ?

Are you making sets by year, and only have the cents ? Your storage technique looks unusual.

 

No I must admit I didn't but I don't think it has turned any browner...but I could be mistaken.
I took the cents out of my album and placed them on a snap-tite "year" holder just for the photos.
The real year sets are stored in Capital holders.