What do you want to see as you look at a coin, and how closely do you need to examine it to find what you are seeking? Both these simple questions are connected in a basic way to the magnification and lighting you use. For this column, I?ll discuss magnification, which is a necessary tool for numismatists ? but remember not to lose sight of the entire coin.
There are a host of things to see on coins. Beginning with an overall view to address its shape, color and design, graders will also be looking at its luster and for imperfections that detract from its eye appeal. Error and variety collectors will be looking for doubling on its design, planchet/striking problems, overdates
and over mintmarks. Authenticators will need to look more closely for die polish marks, tooling and characteristics common to counterfeit or altered coins.
No matter what you are looking for, after a quick perusal, most collectors will seek some type of magnification. Four or five powers of magnification seem to be the norm for many collectors.
At these powers, an entire coin may be viewed all at once, which is especially useful when grading.
Nevertheless, unless you are an experienced numismatist, on most coins you will not be able to see characteristics such as metal flow, die doubling and counterfeit diagnostics using minimal magnification.
Figure 1 is a photo of a Saint-Gaudens double eagle taken at 4X magnification (reduced slightly to fit this page). This view is close to what you would expect to see when using a low-power hand lens. The quality of luster and overall eye appeal is easily determined.
The photo in Figure 2 closely duplicates the view one would see while examining the same coin using a 7X magnifying lens. Now the radial metal flow at the coin?s rim is visible and it becomes easier to determine if any luster breaks on the high points of the coin (Liberty?s knee) are due to cabinet friction vs. wear.
At this power, you can only view large coins a section at a time. A view at 10X, as in Figure 3, provides a much closer view of the coin?s high points ? the top of Liberty?s knee and the dress folds at her breast. At this power, we can examine the coin for circulation wear but we have narrowed our field of view considerably, making it difficult to judge how the bagmarks affect the eye appeal.
One dealer has told me that at 10X magnification ?You cannot see the forest for the trees.? It?s his opinion that this is too much power for coin grading.
Powers of magnification over 10X are best saved for counterfeit detection.
Ten power is also a convenient magnification for variety hunters. Note that micro-doubled dies and any variety needing 15X to 20X to identify may be interesting to find, but they are not universally popular except among specialists. For example, although the major coin price guides lists one major variety of 1972 doubled die cent, I believe variety collectors have identified more than a dozen.
While some experienced authenticators can detect a counterfeit coin using low powers of magnification, or even their unaided eyes, 15X and higher should be the norm for authenticators who are searching for clues to identify new, ?state-of-the-art? counterfeits.
Figure 4 shows our coin at 15X magnification. At this power, characteristics such as the tiny, horizontal, comma-like die defect in the field just below the right edge of the second ?1? become apparent. This is a common size for many counterfeit die characteristics!
An authenticator who has been examining surfaces of genuine coins using high-power magnification will have the jump on those using low power. As the surface quality of new counterfeits approach that of a genuine coin, any differences will still be detectable at