copper spots saint gaudens

The coin that "no one wanted" was in a late gen NGC holer. The cert # is 3336352-003. You can see a picture of it on NGC coin details. The copper spots are below the beak and near the front edge of the wing. If u use the coin details NGC app on your phone you can zoom in. The spots are very subtle, but all dealers noticed them and therefore offered a discounted price. I would be shocked if any dealers gave close to MS65 money for that 1923 if it grades as such. I am very new to collecting pre 1933 gold, but from what I have experienced copper spots are "No big deal" when buying from dealers and a "deal breaker" when trying to sell to them.

Footnote... this is my very limited experience in dealing with buying and selling pre-1933 gold.

 

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GASP! NO! I just can't see that...

 

It's true! I get like that sometimes. Honest!

Chris

 

Do you have documentation to back this up?

 

If you don't believe me, go back and read all of my 16,000+ posts.

When you've finished, I expect you to provide everyone with a complete psychoanalysis citing all pertinent references.

Chris

 

I actually LOL'd here....Funny stuff right there ^^^^

 

I'm not joking. I'm 100% serious. Now, get to work!

Chris

 

+1

 

If anything being NOT difficult would be the gasp shriek eek blue moon uber rare occurence

 

I promised to show the coin after returning from PCGS......

 

If you don't want to read the whole thread, read this citation
http://www.sciencedirect.com/science/article/pii/S1001052107600308

They propose it isn't copper, but instead silver and sulfur. This is why silver dips work on them.

If you want to see the whole previous thread~ a dead one 5 years ago, so don't add comments to it instead of here.

https://www.cointalk.com/threads/cause-of-red-spots-on-gold-coins.126202/

Jim

 

Even John Lorenzo stands corrected. Sure chlorides and sulfur are the two basic surface contaminants but never would have guessed silver sulfide over a copper oxidation. All gold contains silver and then the sulfide due to air exposure - not bad Jim - so far in 2015 the #1 surprise in my world. Will mention this in my new book - somewhere? Great alert - Jim!

 

I was just in envy of their available instruments This was back when the Chinese were having so much 'red spot' trouble with some pandas. The same thread had notice of .999 and perhaps .9999 gold of other countries also having spots, so perhaps there are other effects. I have always had some concerns due to the 'red'color being so much more like 'ruby' glass that had gold chloride or colloidal gold as the colorant. Perhaps the initial 'hole' is started by the silver sulfide, and chlorides can interact with the gold at a later time on a different level of physics/chemistry to produce the red surrounding it.

If we didn't learn new things all of the time, we would be dead Jim

 

I believe you'll find Copper spots are common in a coin consisting of 10% Copper.

JMHO

 

The so called copper spots on modern.999 gold coins are of the size of a needle dot.
Older cold coins like US gold show washed out copper areas of enormous size.
Is this really caused by the same effects?

 

We have three metals: gold, silver, copper reacting with sulfur and chlorine. The analyst detected AgS which is suprising yet reasonable. Read William Weimer - Coin Chemistry - then ask / inquire. Copper (carbon) spots are normally found only on high copper alloy pieces. This is one reason I am doing this new book. We have enough Whitman historical books on the shelves - what we need now (maybe) is ONE metallurgical GO TO book. Just a thought ...

 

Silver sufide may have been the contaminant on that particular specimen just for this type of analysis (ie., this gold coin at this purity level). Given a large of enough sample size, different environmental conditions & varying gold purities we may see OTHER copper oxide(s) & silver sulfide(s) and/or chloride type compounds. Good point - GD JMSP.

Running SEM/EDS on most coin surfaces will always give you chlorine and sulfur withe the ubiquitous carbon and oxygen. Chlorine from water in the air and sulfur from pollution which is universal BTW even on a potato farm in today's time.

John Lorenzo
Numismatist
United States

 

Well a 1 oz 999 fine gold coin weighs 31.1 grams or about 479 grains so that other 1 part would be about .479 grains of almost five times the size of that piece by the pencil point. The copper is only half the density of gold so double the size of that piece again. That .001 part copper is now ten times the size of the piece by the pencil point. And then an area creating a copper spot only need to be a few atoms in thickness. The amount of copper we are talking about is about half the amount used to plate a current Lincoln cent. And the plating on that cent is a LOT more than just a few atoms in thickness. So yes I could see that amount of copper causing good sized copper spots on a 1 oz 999 fine gold coin.