Some oxidation on the copper coin

Hi,

I was reviewing my coins, and found a very unpleasant surprise. On my 1831 EM russian copper 10 kopek coin in NGC slab I found, what I think, new oxidation. What should I do? Contact NCS and send it for conservation? Send e-mail ton NCS first to see if they can remove it?
Thank you.

 

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Looking at the Heritage auction photos, I can see a little something there, but this is decidedly worse. Don't know what they offer as protection assurance, but someone here might know.

 

I can't help you unfortunately, but am curious as to whether or not the oxidation had begun before the stabbing, or if it can develop inside the slab? I know they are supposed to be air tight, but have seen plenty of milk spots develop after slabbing.

 

Actually not supposed to be air tight as far as I know.

 

Not air tight?

 

Slabs are not airtight.

Does not look like oxidation, but maybe residue of some kind like glue. Looks conserve-able to me.

 

Thank you very much! I did see it on Heritage pics, but never looked at it with high magnification. Will try to ask NGC first I guess...

 

Nope, and therefore, not watertight. Good article in the Jan 2009 Numismatist by Donald Beussink, who had his collection in a safe deposit box in a bank. Bank flooded and water rose high enough to enter his box. Some of his slabs had water in them. Some lessons: Bank vaults and slabs are not watertight. Best to have a safe deposit box that is at least waist level.

And don't swim with slabs in your pockets.

Cal

 

This surprises me. I guess I've always assumed that "sonically sealed" actually meant sealed. Encased IS a better description, or just slabbed.

 

The new PCGS slabs are watertight, NGC has never claimed there's to be so I doubt there's are as well. Neither are airtight and both are sealed.

 

Might as well self slab. My grading can be just as wrong.

 

How can the slabs be water-tight, but not air-tight? And what does it mean to be "sealed"?

 

Because air is harder to seal off than water.

 

Air molecules are smaller and they don't have the hydrogen bonding attraction between them that water molecules do so they can pass through much smaller openings than water can. Also the plastics will over time allow gases to "percolate" right through them slipping through the open spaces between the molecules that make up the plastic

 

My questions were actually rhetorical in nature. It's impossible to seal off air or moisture using plastic materials. They are permeable to both air and water and the insides of the container will eventually reach equilibrium vs the outside.

 

Water can be sealed. They did it. Air is a different story and much more expensive. But yes you throw something into the ocean it'll leak at some point

 

A well-known dealer once dipped a Peace dollar while in its slab. The only problem was getting the dip rinsed off and getting the coin dry afterwards. True story.

 

I looked at the NGC cert photo and didn't see anything nearly that pronounced. It definitely looks like it emerged after slabbing.

 

Yes, water can be sealed, but not with plastic no matter what PCGS tells you. It takes a "glass" material to make a hermetic seal.

Perhaps you're thinking of "water" in its liquid state, and that if you dunk a slab into a glass of liquid water, it won't fill up. If the plastic is "sealed", then this is true over short time spans. This is generally called "water resistant". But over a longer time span, water will eventually seep-in through imperfect seals or directly through the plastic via diffusion. This happens even if it's not dunked into liquid, but through diffusion from the moisture in the atmosphere.

It's generally not good practice to seal plastic containers that are meant to stay as dry as possible inside. Eventually, the inside atmosphere will reach equilibrium with the humidity level in the outside environment. If the container is then brought to a colder environment, the moisture inside the container can condense on the inside container surfaces and onto the contents (ie coin). For this reason, "sealing" a slab is actually a bad idea. It's better to have a small leak hole to allow the atmosphere to equalize when subject to changes in temperature and humidity levels.

No matter whether the slab is sealed or not, the only way to keep it moisture-free inside is to keep it dry outside. Putting slabs into an environment that is kept dry (typically with dessicants) will keep their insides dry. In fact if you put a "wet" slab into such an environment, it will gradually dry out as moisture diffuses through the plastic!

Keeping oxygen and sulphur from your copper and silver coins is a bit tougher. In the semiconductor industry, we have "dry boxes" that are constantly pumped with dry nitrogen to ensure no moisture or reactive air molecules (Nitrogen has low reactivity at room temp) are present that might cause problems. Most folks don't have the resources to contemplate such a method, but some dealers or deep-pocket collectors with safes might consider it. Pumping dry nitrogen into a safe would not be prohibitively expensive, and would help maintain the coins inside in an excellent long-term storage condition.

 

It looks like that will come right off at NCS. IMO, NGC owes you nothing and you should have to pay for conservation and reholder. Now, a suggestion: If you call customer service and really whine nicely that the spot has grown, they MAY give you a discount.

I posted a thread on CU named "Do Slabs Float." Too long to say what's in it - go look if interested. Anyway, I submerged a slab for a week with no evidence of leakage. I also found that slabs from ICG with coins under a certain weight (3c silver was one) actually float. I'm waiting to test a PCGS or NGC slab with a 3c to see if it floats. Most coins in all TPGS slabs sink like a stone.

The "damaged" coins mentioned above were submerged for over a week in flood-contaminated water (gasoline, poop, salts, etc.) That and the pressure of being submerged more than a few inches may be why the coins were attacked inside the slabs. Slabs are not watertight!

Just saw the post above. Wow, thanks! Oh, another tip for poor folks: Store your slabs in boxes filled with white rice! Don't forget to change it out once a month or when you need rice as a side dish for dinner.