Higher Powers of Magnification

Posted by Skip Fazzari, Authentication Consultant to NGC, on 5/21/2008

A set of high-magnification hand lenses is an invaluable tool for numismatists. However, magnification of 10× and up is only recommended for spotting signs of counterfeiting. Skip Fazzari offers these tips and more.

There are a host of things to see on coins. No matter what you are looking for, after a quick perusal, most collectors will seek some type of magnification to enlarge their view of the coin they are examining. I travel with an assortment of hand lenses. There is a 20×, a 10×, and a combination 3×/4×/7×. Beginning with an overall view to address shape, color, and design, a grader will also be looking at a coin’s luster and for imperfections that detract from its eye appeal. Error/variety collectors will be looking for doubling on its design, planchet/striking problems, overdates, and overmintmarks. Authenticators will need to look more closely at its surface for die polish marks, tooling, and characteristics common to counterfeit or altered coins.

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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, you will not be able to see characteristics such as metal flow, die doubling, and counterfeit diagnostics on many coins when using minimal magnification. The micrograph shows the head detail of a genuine 1861-O “CSA Obverse” Seated half dollar. This view is close to what you would expect to see when using a 10× hand lens. The quality of its luster and surface is easily determined. The diagnostic die break through Liberty’s nose is sharp. At this power, a few radial flow lines are visible at the coin’s rim and it becomes easier to determine if any luster breaks on Liberty’s breast are due to cabinet friction or friction wear from circulation. Note that at 10×, you can only view large coins a section at a time. We can examine the coin for circulation wear but we have narrowed our field of view considerably, making it more difficult to judge how any bag marks affect the eye appeal of this specimen. One well known dealer has told me that at 10× 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 10× are best saved for counterfeit detection. Ten power is also a convenient magnification for variety hunters. Higher powers may also be used; however, most micro-doubled dies and any variety needing 20× to identify may be interesting to find but they are not universally popular at the moment except by some collectors and specialists. For example, although the “Redbook” lists just one major variety of 1972 Doubled Die cent; I believe variety collectors have identified more than a dozen varieties of this cent with smaller amounts of doubling.

While some experienced authenticators can detect a counterfeit coin using low powers of magnification or even their unaided eyes, 10× and higher should be the norm for authenticators who are searching for clues to identify new, “state-of-the-art” counterfeits. At these powers, characteristic defects transferred to the fake by counterfeit dies become apparent.

This article was previously featured in Numismatic News.