Do gold coins tone?

Yes, gold tones. Here's a piece I bought from mark feld:






And pure gold tones too, here's a "4 9's" (pure gold) Gold bar.



One dealer I took the 1834 coin to even said he thought it was AT', which isn't true, his reasoning was because 'only one side was toned', he probably hasn't seen many examples of these coins.

 

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GoldCoinLover, I don't think your quarter eagle was AT'd but I do think it was dipped at some point and re-toned, you can tell by the bright untoned areas around the stars and date.

 

I always thought those halos around the stars like that indicated cleaning, but I guess dipping could be an explanation as well.

 

US gold coins, the type of which have been shown in this thread are not "pure gold".

 

I've talked to several people about this, including mark. Gold doesn't typically re-tone, especially like this one. The area's around the stars are also where the luster still is, the coin was probably once more PL, and as it wore down from circulation only the protected areas of the coin remained with luster and semi PL on the obverse. It may have be dipped sometime ago in its past, but I doubt it.

I've seen numberous quarter eagles like this and it is just how they were made..it has nothing to do with a dipping or cleaning.

It really bothers me when people say this, because I have to explain it to them, I think it's an orgininal coin and every dealer I've shown it to in hand thought so, as well as CAC, mark, and NGC. You can also talk to physicsfan on NGC.......he said this to me:

"The thing is, in photographs online, the luster around the stars can appear similar to an effect of cleaning - for good reason. When a coin is cleaned, the protected areas around stars and in lettering are the areas which don't get polished - just as these same areas are the ones which retain their original luster the longest in circulation. For this reason, when looking at a picture online, when these areas look different, as they do on your coin, it is sometimes a tipoff that it might have been cleaned."

 

Keven, you don't "have to explain" anything to anyone if you don't want to. And remember, you and I have seen the coin in hand, and posters here have not. Based just on the images, I probably would have thought it was dipped too. Maybe it has been, I don't know. But as I remember it, my guess is no. Keep in mind, NGC and CAC need not thought it was original to have graded it and stickered it, respectively.

Enjoy your coin and don't worry about what other people think of it, especially based on on-line images.

 

I am not a chemist. It would be interesting to get the answer from someone who is. But I don't believe gold oxidizes in the presence of oxygen, which is what normal tarnish/toning is. So technically, I don't think pure gold really tones. If a gold coin tones, it is more likely that it contains some other metal or impurity, regardless of what the fineness is stamped on the coin. That said, I think gold is somewhat reactive with certain acids, so perhaps handling them or exposing them to an environment that contains certain acids will cause them to discolor.

 

Before I put my .9999 pure gold buffalo proof coin into the safe deposit box I noticed a red spot on the obverse and one on the reverse. Now, that coin came from the mint in 2006 and has never left its airtite that it came in. I never opened it and always kept it in a safe with silica desiccants. I wish I'd taken a photo of it because I want to see if it grows! The spot is more red than brown, and wasn't there when I bought it in '06. I thought I had seen a thread on Buffalo gold toning but I haven't been able to find it with the search button. Does anyone remember that thread?

Bruce

 

A really ugly one.

 

Just to be clear I never mentioned anything about polishing or cleaning which would create hairlines or ruin the surface, dipping if done right would retain the luster. If gold can tone once it can tone again. That is my opinion.

Now as far as my comments go I was going strictly by the photos and as Mark said it is possible especially if not seen in hand as I have not to come to my conclusions.

 

You shouldn't let this bother you. I know we have discussed this coin here in the past. You have to admit, the photographs do look suspect. Because this coin once may have been very PL...it is likely a hard coin to photograph accurately. Coins can't really be evaluated in photos and this is an example of why. This coin looks cleaned in the pictures. But, as you have said (as well as some experts)...it's not. It's just the picture. So, please don't get upset when someone looks at these photos and thinks the coin has been cleaned. The photos have that look...even though it is wrong.

Maybe it would help if also posted a picture of the coin in it's slab...that might help in the future if you don't want to have those comments.

 

Generally, if one asks if gold tones, they are asking does gold change color due to a chemical reaction ( oxidation) like silver or copper. Copper and silver are commonly mixed with gold ( not chemically combined) for coins or jewelry. It is simple to say that copper or silver mixed with the gold does oxidize and if the mixture is good, the size of each part should be microscopic enough that the hue of the entire coin will change in the eye's view. One would expect 90% gold to tone more than 99%, and even more so for 99.99%. If the mix is not good and "clumps" appear, the clumps may be large enough to be visible and may have copper red to brown hue or if for silver, other silver tone colors can shade the gold's hue.

==========the below is not necessary if you don't like chemistry==

The problem is that this reflects "old time color chemistry" whereas since the 1970s, the color of gold, due to it's mass and electron configuration has been determined to be altered by relativistic quantum effects on the atoms of the metal gold. So the color of gold itself can be affected by especially silver atoms adjacent to the gold atoms. People who deal with gemstones have had to come to this theory many times already to describe how molecules like iron can give so many different color hues in gems. So even though gold may not oxidize, it is theoretically possible for gold to change color due to changes within the electron energy configuration. But the purer the gold, the less the change possibility.

Go down to the "Color of Gold section".
http://en.wikipedia.org/wiki/Relativistic_quantum_chemistry

Jim

No posting indicating that I should have gone to bed earlier is necessary :whistle:

 

Guess you missed my answer. Basically Gold doesn't combine with many, many other elements or compounds. It does not Oxydize if you think that all toning is Oxygen based. Gold does combine with some gasses such as Chlorine or Flourine though. The worst thing for Gold is the presence of so much SO or SO2 in the air. Sulfur also reacts with Gold to form Au2S. Many areas where Sulfur Coal has or is being burned creats the SO or SO2 in the air, mixed with Moisture, H OH, it forms an acidic gas that attacks many, many things. You may have heard the expression ACID RAIN. What I just described is exactly that. This causes Copper items, pipes, ground rods, lightning protection systems to disintigrate. AND, the forming of Au2S on your Gold Coins.
Toning on coins is an expression and although many may just say corroding, tarnishing, rusting, rotting, etc., this toning is a combination of a metal and other substances. True that Gold mixed with other metals may take on different tones due to the other metals combining with different substances that Gold does not combine with.

 

We often cross the line between chemistry and numismatics.

Chemically, pure gold is "inert" - relatively speaking. Relative to most other metals, it has very little electronegativity, so it doesn't ionize as easily. It doesn't react with other compounds as easily, but it can be made to react.

That's chemistry.

In numismatics, however, we are never dealing with pure gold. Never ever. The impurities in the gold react, and more importantly, surface matter on the gold - oil from fingers, etc. - reacts and tones.

 

I say "forget the chemistry, stick to numismatics" and what anyone can plainly see is that gold coins tone.

Not as much as other metals, not the same way as other metals, but they do tone. In their own way, in their own time.

Forget the chemistry textbook, and look at the coins. What do they tell you ?

 

Doug, I don't know what coins you're speaking of, but most older US gold type coins are listed at .900 gold and .100 copper.

 

I checked out all of my .9999 gold First Spouse coins and none of them appear have any toning yet. Will keep my eye on them though, but maybe they are pure enough to not tone???