Copper Stains on Gold Coins – A Mostly an Overrated Problem

[BillJones]

Last summer a customer purchased a nice gold coin from me at a show and then asked about 1907 High Relief $20 gold piece. I told the customer that the coin was obtainable and that acquiring one was more a matter of money (and lots of it) than finding one for sale. After the customer left, I did find one at the show and took it on consignment.

 

The customer never responded to my phone calls that I had a piece to show him, but I did get an education about how much copper stains on gold seem to matter these days. The coin I found was a PCGS MS-64, it was “all there” IMO. In fact it was so nice that I was prepared to trade up my MS-63 for it, but the owner and I could not come to terms.

 

What amazed me was when I showed to a couple of dealers, their attention immediately focused on a couple of light copper stains that were near the sun on the reverse. They expressed the opinion that those stains were real negative to the piece, which surprised me.

 

Copper stains appear on gold coins when there is a less than perfect mixture of alloy in the piece. Although we refer to U.S. gold coins as “gold” they are in fact made of 90% gold and 10% copper. The copper is necessary because pure gold would be far too soft to withstand the rigors of circulation. Where there is a small concentration of copper in one spot, it can change color, just as does in a copper cent. Therefore small brown spots, which rarely intensify to dark blue are seen.

 

For years collectors have regarded this form of toning as something that went with the territory. Many collectors thought that it was better if they were not there, but if the coin graded MS-64 or less it really didn’t matter. At so some it was a clear indicator that the gold coin was genuine since it was thought that it took years for such toning to form. That, alas, is an incorrect assumption.

 

Today it seems that attitudes have changed. Now it seems that many original gold coins are going to the restoration services for dip to remove these “problems.” Sadly there are prices to be paid for this.

 

First, a dipped gold coin loses its original look. Most such pieces take on a “white gold” appearance, which many advanced collectors find unattractive.

 

Second, there is a good chance that the copper stains will return in a couple of years. The reason is that only the surface oxidation has been removed. The “vein” of copper that formed the spot in the first place is still there and ready to re-emerge.

 

I’m not going to say that it is wrong to try to remove ALL copper stains from gold coins. Some pieces are genuinely unattractive, and if the problem can be effectively removed, the coin might be improved. Still I think that the situation has gone too far, especially in the case of early U.S. coinage. Far too many pieces how have an unattractive pale appearance, and in the eyes of many of us, too many pieces have impaired forever to satisfy the demands of a poorly informed minority of collectors.

[MarkFeld]

Second, there is a good chance that the copper stains will return in a couple of years.

I have actually heard of instances in which they reappear much more quickly than that.

 

I usually don't mind copper stains on gold coins and in fact, sometimes I find them to be an attractive/appealing hue. However, I know many dealers whom will either avoid or discount such pieces.

[Wihlborg]

I know many dealers whom will either avoid or discount such pieces.

 

And there is a very good reason for that in my opinion. It is because while I may be in the minority, although I don’t really believe that, if I were going to spend the money on a MS-64 high relief saint it wouldn’t be on an example that has copper spots. I would pass on such pieces until I found an eye appealing example without spots. Most dealers won't buy what they can't sell

 

John

[DirtyGoldMan]

I agree completely with your sentiments, BJ. Doug Winter recently posted an article on his website, which cannot be retrieved at this time, which had a very similar viewpoint. In unusual circumstances, a large, poorly placed copper spot or extensive copper spotting can be a real negative, but most of the time, it is no big deal. Many coins have undoubtedly been ruined to correct a problem that is:

1) Uncorrectable

2) Not a real problem.

[Oldtrader3]

Some series (i.e. Coronet half-eagles) are more affected by this problem then others. Several years ago, I built an almost complete set of MS, 1900-1908 half-eagles. Almost all of the "S" mint coins and several of the Philadelphia coins had copper spots. The origin of gold for Philadelphia minted coins was always unknown. My half-eagles were originally toned MS63/64, PCGS and NGC certified coins. When searching for specimens for this set, almost all of the "S" mint coins that I examined had some copper spotting. Some year's mintages were worse than others.

 

Copper spotting appeared to be more of a problem for half eagles than for Coronet, quarter eagles or eagles that I have owned. Although I have noticed that gold dollars often have this same problem. I suspect that alloying technology for gold coins minted before 1910, was less than optimal. I know that gold refining before this period could not always produce higher than 98% gold alloy purity. Maybe the poorly refined gold trace elements, combined with poor furnace temperature control and incomplete mixing all contributed to this problem.

[DaveG]

I've always thought that it was the guys who traded Saints in quantities who worried most about copper spots.

 

For example, I was at a dealer's table a while back when a wholesaler came up to him and offered him "20 common Saints in MS-63 - no copper spots".

[James_OldeTowne]

When I see copper spots on a gold coin, my instant reaction is "Wow, a coin that hasn't been messed with!". I'm much more concerned when a gold coin looks "too perfect".

[MikeKing]

Interesting post.

Doug Winters I feel is one of those few dealers who offers a real education to collectors. I admire him greatly, I've emailed him in the past, and he's always been gracious. I also learned a lot from his web site, although I've never bought a coin from him. Someday.

[stinkycheese1]

I have a gold sovereign that I keep for future reference: It was a 1913 gold sovereign with a large copper spot. I didn't know what it was so I scratched the copper spot off! ANACS net graded it AU-55 UNC details.