A Basic Guide to Detecting Doctored Gold Coins

There is no getting around the fact that doctoring of rare United States gold coins is a problem in the market. Doctoring is not new. I've heard stories of American collectors and dealers "messing" with coins as far back as a century ago, and I have no doubt that the problem dates back even further in Europe. But it is really only the last decade or two that we've seen increasingly sophisticated doctoring done in an attempt to fool the grading services. At first, I thought about using lots of photos to verify what I am going to discuss in this blog, but I don't want to taint specific coins that don't belong to me by pointing out obvious doctoring. So I am going to be as descriptive as I can be without using images. Hopefully, this will work.

For me, one of the most obvious ways to detect a doctored gold coin is by looking at its coloration. One of the reasons that I spend a significant amount of time describing the coloration of specific coins in my books and on the descriptions of coins in my inventory is so that collectors will become familiar with what natural color is supposed to look like.

Once a collector becomes familiar with the way a coin is supposed to appear, it becomes easier to detect coins that don't look the right way. For instance, the early date Dahlonega half eagles have a specific deep green-gold color that is easy to appreciate. Conversely, an issue from this era with the "wrong" color will not look right to a collector who is familiar with the series.

Many of the people who doctor gold coins aren't great numismatists, so they don't necessarily know the right color for an 1840-D half eagle or an 1878-S eagle. Becoming a knowledgeable numismatist within your field of collecting will put you in a far better position when it comes to determining whether or not a coin has been doctored.

There are a number of different types of artificial coloration that are found on gold coins. These depend on the specific chemical that is applied and how the process is undertaken.

Typically, chemicals placed on gold coins break down after they have been on the surface for a period of time. When you see a gold coin that has crazy color in a PCGS or NGC slab, this color didn't exist on the coin at the time it was graded; it changed within the slab.

One color that doesn't naturally exist on gold coins is deep orange or what I refer to as "Cheeto Orange." Think of that crunchy corn snack and the color it left your hands after you ate a few handfuls. I see many United States gold coins in holders that have this flaming orange hue. In 100% of the cases that this color is present, it is artificial,

Another color that indicates a coin that has been doctored is deep reddish-gold. There are many gold coins that have natural reddish-gold hues, but the hues that they possess are subtle and tend to deepen towards the borders. Coins with fake red color almost look like they've bled as the result of being stabbed. This deep red color doesn't exist on natural, original coins.

I see 20th century gold coins from time to time that have a bluish or purple tint and this is the result of the surfaces having been heated; probably in an attempt to remove spots. Back when copper spots were not considered a detriment, you never say any U.S. gold coins that had blue hues. Today, with copper spots being the numismatic equivalent of melanomas, you see fewer gold coins with these spots and more with funky heat-produced hues.

Many of the U.S. gold coins that have been doctored have had substances put on the surfaces in an attempt to hide hairlines or marks. Often times, substances such as auto body putty or dental wax are lightly coated on the surfaces.

Why are these substances not detected by the services when the coins are submitted? Some are, but on other coins, the application is light enough to not be easily detected. After a period of time, the putty begins to break down and it turns cloudy or even white.

Putty that has broken down is easy to spot. How can a collector spot fresh putty on a coin? It's not easy; it can fool both the services and savvy dealers, myself included. In this case, I think its as important to "buy the dealer" as it is to buy the coin.

Certain dealers have reputations as people who doctor coins. As you become more experienced in your area of specialization, try to learn what dealers have these bad reputations. If this isn't realistic, study the coins on their website. Do they show signs of having been puttied?

This very problem is a reason why coins in old holders have become so popular with collectors. The chances are good that a coin slabbed by NGC or PCGS in the early 1990's is not going to change dramatically in appearance if it hasn't already in two decades within a slab.

I'd suggest that whenever you do get the chance to study coins that are 100% fresh (from old collection, in old holders, etc) you pay careful attention to the quality of the surfaces. What is a gold coin that hasn't been doctored supposed to look like? Make mental notes of original surfaces and use this as a comparison for coins in your collection or those you are thinking of buying.

A less innocuous type of doctoring involves artificially brightening a coin by stripping its surface. The most common way to do this is by placing a coin in a solvent such as Jewelustre and "dipping" it.

While I am much more of a purist than most dealers, I do not have an issue with gold coins that have been carefully dipped. Of course I would rather see coins that are dark and crusty, but a lighter coin with mostly full "skin" is commercially acceptable. On certain coins, like Brilliant Proof gold, it has become the rule rather than the exception and many collectors of Proof gold have literally never even seen a truly original example.

There are other ways of brightening coins that I personally do not care for. At one time, it was common to see gold coins that had been "baking soda-ed" in a way to simulate mint luster by making them bright and shiny. Unfortunately, many gold coins with this sort of appearance were graded and encapuslated (and often "maxed out" from a grade perspective, in my opinion).

Coins with this sort of appearance have fallen out of favor and the services have become much better about putting such coins in overgraded holders.

How do you tell a gold coin that has had this done? Often the appearance is grainy in texture and the color is drab and almost monochromatic in hue. Also, the surfaces will lack any cartwheel luster, although this may be difficult for a new collector to determine. The best thing is to, again, learn what original surfaces look like.

To me, the worst type of doctoring is the sort that involves moving metal on the surfaces. This is deceptive and dangerous to the hobby. Luckily, the grading services are extremely good at detecting coins that have had this done, and for most collectors this will never be a problem unless they move out of their comfort zone and purchase raw coins from non-reputable sources.

If you do purchase raw coins, there are a few things to check. Collectors often forget about a coin's rim and should remember that this is the third side of a coin. Some 18th and 19th century coins have been cleverly rim filed in an attempt to remove old bumps and bruises.

Other raw coins have had scratches or marks removed. Often, it is easy to detect this as they will show smoothed areas in the fields. The grading services are extremely good at detecting this and I can't recall having seen many gold coins in holders that had scratches or marks removed but missed.

Will the coin doctoring problem that we are facing go away any time soon? It is doubtful but as a consumer, you can do your share in eradicating the problem by becoming knowledgable. If coin doctors lose their audiance for doctored coins, they will stop (or at least cut back) on their work. This sounds naive, I know, but in this case an educated consumer is one solid way to begin eradicating this problem.

What are your thoughts on coin doctoring? Leave a comment after you've read this blog and let's begin a discussion.