Unusual "reaction ring" from an impurity on a Proof SE. Show us yours.
Insider2
Posts: 14,452 ✭✭✭✭✭
This is the usual "reaction ring" seen when some debris remains on a Proof SE.
This is one type I've not seen before. There is a linear impurity into the coin that has produced the discoloration.
1
Comments
My YouTube Channel
looks dirty to me
Best place to buy !
Bronze Associate member
Surface contamination is the initial cause of nearly all "copper spots" on gold.
hmmmmm
@RogerB I've never heard that before and it doesn't make a lot of sense to me. Would you please explain your thinking? Thanks...Mike
The other .001
OMG !!!
It is not my original idea.
This has been demonstrated numerous times by museum professionals and several international mints (including China and Austria, I recall) as part of collection preservation and attempts to prevent "copper spots" on gold coins. There are several published academic articles and the situation is discussed in my new book on Saint-Gaudens Double Eagles.
A minute speck of impurity - such as silver - acts as a chemical reaction nucleus from which a visible black spot occurs and it is surrounded by an expanding halo of contamination as molecules migrate. In China, they determined that gold had to be handled in rooms that were completely sterilized and isolated from silver - including ventilation systems and clothing....Essentially a gold-level clean room approach.
(For those who wonder why slabbed modern gold and silver seems to spot more than pieces kept in original packaging, this is part of the answer. TPGs do not enforce clean-room conditions throughout their process; contamination is rampant. US Mints aren't a lot better but mechanization helps avoid some problems. The Mint's new bulk shipment program will help reduce spotting because it reduces exposure of the coins to contamination.)
While a lot of what Roger has said is true, from personal experience, I say...Actually, I cannot write what I want to say and that should give members a clue to my thoughts. This silver thing for example. It should be very easy to disprove. Take a gold coin and put some 90% silver shavings on it and let it sit until the silver turns black. There will either be a brand new copper spot or not. End of experiment. LOL.
Experimentation with coin surfaces is an intriguing area. I did this for about two years around 2001/2002/2003 time frame. It is a vast area and by no means did I even 'scratch the surface' - to 'coin' a coin phrase...
I tried many methods of tarnish... I did not get down to the minute contamination level though... It does sound logical from what I have learned in my metallurgy courses and experimentation. Cheers, RickO
It'd be cool to see what would happen to gold if it was dipped in water, covered in silver dust and let sit in the sun in old acid paper.
Museums and world mints have already done the work. The contamination is not from silver shavings - it comes from minute particulates, dust if you will, blown about that land on a coin.
@RogerB
When you posted this: "A minute speck of impurity - such as SILVER -
My BS detector SCREAMED. Sham on those researchers.
As I wrote, most of your post was great. Most of the spots on silver proofs are from debris contamination. I'll post more images. Most of the contamination on gold is from impurities in the coin or struck into it. I have NEVER seen a piece of debris stain a gold coin enough that a "huff" of moisture on the coin and on a Q-tip did not remove it quickly and easily!
Silver was identified by China as the primary culprit. It is also implicated in US West Point Mint gold spotting by independent testing of the spots - mostly silver compounds.
The international researchers are far more knowledgeable and thorough than anyone with any TPG. Also, you need to get your "BS Meter" fixed -- maybe an upgrade of knowledge, or at least a mind opener, will help!