Struck Plated Blanks Reveal Flaws|
October 16, 2012
This article was originally printed in Numismatic News.
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Ever hear the old expression, “Back in the saddle again?” For me the most rewarding aspect of numismatics is teaching and I just returned from Cleveland, Ohio, where I gave a three-day grading and authentication seminar to a dozen students. Several of them commented that they could tell how much I enjoyed teaching – it was that obvious. As most had never been exposed to the actual “study of coins,” we had a lot of ground to cover in three days. Having been in their shoes myself back in the 1960s, I was able to instruct them using the same path of development I took to become a professional numismatist. It is a proven method I’ve used since 1974. When I teach a class, I always learn something new. That’s what inspired the subject matter of this column.
A short time ago, I wrote that I don’t test coins (except 1943 coppers) with a magnet. On one occasion I have seen it done; but the magnetic fake was so crude that an experienced collector who was familiar with the characteristics of that type of coin would not be fooled. Things have changed.
One of the students brought a fairly deceptive counterfeit Mercury dime to the class. It was a pretty specimen; however, the coin looked “too good to be true.” Mercury dimes with virtually no marks and blazing luster are quite common but not those dated in the teens other than the 1916. That alone should have given the buyer pause to check the coin further as this example was slightly underweight and magnetic.
Many counterfeit coins that are not magnetic fall into the “To Good To Be True” category and that is one characteristic I teach students to look for.
The class had a second surprise. Those readers who attended the ANA show in Philadelphia might have seen a salesman demonstrating a hand-held XRF Spectrometer Analyzer to test the composition of metal objects such as gold scrap, bullion, and coins. He came up to Cleveland to demonstrate the device to my class. What a practical tool for authentication; however it’s very expensive to own. I won’t push a commercial product here so write to me if any dealers or metal buyers wish further details.
Using the device, we were able to analyze the metal content of several counterfeit and genuine coins in just a few minutes. I was especially relieved to confirm that a counterfeit British sovereign I use in my teaching set was truly a gold-plated, platinum specimen.
One of the students had a dark about uncirculated 1928 Peace dollar whose authenticity had raised divided opinions between several dealers. In my opinion, the coin was an extremely deceptive counterfeit. It was probably similar to the one I wrote about last month. Now, I have actually seen two of these coins that I had read about previously; and it’s a good bet that these fakes have flooded the market. The salesman performed an analysis of the coin with the XRF that confirmed my suspicion that it was counterfeit. Then he talked about the newly discovered altered gold bars that were filled with tungsten.
Since the specific gravity of gold and tungsten is virtually identical to the tenths (19.3), these should be very difficult to detect. However, the XRF analyzer would have discovered the discrepancy. To prove his point, he passed around two purported .999 fine silver Engelhard “Prospector” rounds to see if we could determine which was actually silver and which was a silver-plated, copper counterfeit. He said that they both were within tolerance as far as their weight but some students claimed the silver-plated specimen seemed to be slightly larger. This is a case where a specific gravity test would have revealed the fake but what dealer is going to run a test on a perfectly genuine-looking silver round?
When my turn came to examine the pieces, I viewed them using a stereo microscope and the clue to which specimen was plated became apparent. Adjacent to the sharp relief where a letter raised up from the field was a tiny sliver of pinkish copper color that contrasted with the prooflike silver surface on the rest of the coin. Apparently, the copper planchets of these fakes are silver plated before they are struck. During striking, there were a few areas where the force of the strike caused some of the plating on the planchet to “pull away” from the design as the metal filled the die. This exposed a tiny sliver of the copper under the plating. Readers can find an actual example of this “shearing effect” by searching Lincoln cents made after 1983. The micrograph here shows an example of this characteristic on the reverse of a 2000 Lincoln cent.
The three pillars of the Lincoln Memorial show various degrees of “clad layer spreading” that may be present on die-struck plated coins. You can see how the clad copper surface contrasts with the dark zinc alloy of the coin.
It’s getting harder to stay one step ahead of the counterfeiters. Contact me at P.O. Box 1007, Tallevast, FL 34270 if you are interested in one of my classes. I also highly recommend you take courses at the ANA Summer Seminar as it is less expensive. Who knows, you might even have me as your teacher one year.
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