The adage, “You can’t teach an old dog new tricks” should not apply to professional numismatists as we must be both vigilant and open-minded in order to detect the latest batch of fakes produced using evolving technology.
This is good in theory but it is not always the case.
No one can argue that the most experienced authenticators are getting older – the best are probably approaching 50. As a young man during my early career, I had interacted with one or two “old dogs” who were resistant to change of any kind. Imagine how frustrating it would be if one professional incorrectly asserts that an obvious deep scratch in a coin’s surface is actually just a raised line due to die polish. That’s like a Nobel Prize winning mathematician saying 2 + 2 = 7!
Let me take a moment to express a well proven and demonstrable fact: The ONLY way to see every characteristic on a coin’s surface is by using both eyes, a stereo microscope and fluorescent light – PERIOD. That’s the way it was done at the U.S. Mint’s laboratory.
Nevertheless, some “old dogs” either rarely use a scope, or will not even consider walking across a grading room to try using one in combination with fluorescent light. It is no wonder they often conclude that 2 + 2 = 7! It is very frustrating when professional opinions differ only because one party is too stubborn to use all the tools available.
In my authentication/grading classes, I like to compare the tools I use daily to examine coins in this way: You can cross the United States on foot (naked eyes), in a horse drawn wagon (hand lens) or with a jet plane (microscope). Unless you wish to take in the scenery, the last is faster and gives a better result. Enough said.
I wish every numismatist had the luxury of a few hours of instruction using a stereo microscope and fluorescent light to view some genuine coins. They would quickly learn the characteristics of a coin’s surface. Later, they would often be able to quickly/correctly identify similar characteristics using only a hand lens. Without this experience, I have found that even well-regarded professionals will disagree on what they see on a coin. For example, on numerous occasions I have witnessed a disagreement regarding coins that are weakly struck or struck through grease.
Struck through (Struck thru also used.) errors occur when there is a foreign substance between a planchet and the dies as a coin is struck. Usually this type of error will be caused by lint, thread, a dirt particle, or blob of grease. If the offending debris is no longer attached to the coin, we are left with a depressed area that looks different from the rest of the coin’s surface. Sometimes the surface of the depression itself will provide a clue as to what made it.
For example, the cross-hatched pattern from woven fabric (a rare occurrence) provides an easy ID. Figure 1 shows a 2009 Ultra High Relief $20 struck through thread. Some of the remaining thread and its reflection are visible in the micrograph. In any case, the surface of a newly made coin will be original and the struck-through portion should have a uniform appearance. Sometimes, coins having a detached lamination can mimic the appearance of a struck-through error. A lamination occurs when there is a weak bond in the coin’s alloy caused by foreign material or improper mixing. Lamination defects should exhibit a “ripped-up,” or split surface at an edge.
There are many reasons a Mint State coin will appear weakly struck with loss of design details. A weak area on a coin due to striking will be uniform yet appear different from the original surface. Weak strikes usually cover a larger area of the surface than struck-through errors. They occur most often on the high points of the design, or around the coin’s periphery. Additionally, there will not be any pattern or roughness left from foreign material on their surface. Weak strikes do not penetrate deeply into the surface. Very often the remains of any original planchet surface imperfections – I call “OPSI” marks – will not be struck out and therefore remain visible. A loss of edge detail will often provide proof of a weak strike.
In Figure 2, the weakly struck portion of the Lincoln cent design appears as a flat, unstruck area lacking the normal relief. I coined the term “Flat-Strike Luster” to describe the oddly frosty surface found on areas of weakness – in this case the tops of the flat letters. While this surface is original, it is completely different in color and texture from the normal surface of the coin. The surface found on struck-through portions will NEVER have this type of luster. The interior of a struck-through error will either be dull with the same general color as the original planchet; or shiny depending on the coin’s original surface.
Figure 3 shows a Morgan dollar that was struck through a particle of sawdust used to dry planchets at the Mint.
You may find coins in the marketplace such as the Lincoln cent above described as “Struck Through Grease” when they are actually weakly struck coins. This is an example of something that even an “old dog” should not refute.