Recently coin doctors have been concocting sulfur solutions or applying heat–to the point of baking coins in vegetables–to come up with a pastel tone that really only occurs naturally in old Hallmark and PCI holders.
Admittedly, those true pastel tones are breathtaking. They often appear in concentric circles with yellow, gold, orange, red, green and blue as if an artist water-colored them on silver.
Here’s an example.
Note how each color blends into the other and the conspicuous label, “100% White.” The chemical composition of the paper label causes the toning over a number of years.
Now compare that to the artificial pastel that is created via heat. There are many ways to do this, wrapping the coin in foil or even inserting it in a potato and then baking in an oven at a certain temperature; but the purpose here is not to encourage coin doctoring so I won’t be specific. Suffice to say, though, that the “pastel” will seem detached and even grainy with the silver taking on a burned look as in this doctored coin on the auction portal Proxibid.
Ebay may have banned replicas (although we find them consistently in fake California fractional gold); but it hasn’t cracked down on artificially colored coins. If you do a search on eBay with the words “toned silver eagle” you may find far more artificially toned coins than natural ones. Many of the fake-colored coins are treated with sulfur-based solutions or greases (Vaseline is a preferred product).
The colors of chemically treated coins can be hideous, as in this amateurish example.
One of the ways to check on a seller is to view his entire consignment on eBay or other portal. If they all are “toned” without being slabbed by PCGS, NGC, ANACS or ICG, as in this page below, you can bet the seller is a would-be alchemist unable to perfect his craft.
For more on detecting artificially toned coins, visit this PCGS’s page, “Detecting Doctored Coins.”
You’ll also find several guides on eBay. Here is a useful one.
Naturally toned coins are bringing ever higher premiums, explaining why so many are willing to doctor otherwise appealing coins. The best way to prevent the practice is to know how to detect the altered lots and avoid sellers who profit by them.