Your most valuable tool when collecting.
A set of magnifying glasses are an invaluable tool for numismatists(coin collectors). However, magnification of 10× and up is only recommended for spotting signs of counterfeiting. 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.
Try to travel with an assortment of hand lenses if you are a serious collector.
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. Expeirenced Collectors or Dealers will need to look more closely at its surface for die polish marks, tooling, and characteristics common to counterfeit or altered coins.
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.
It Takes time to become an expert at grading a coin or noticing its slight imperfections or errors, with some practice with a magnifying glass over time will help you appreciate and be amazed at what a coin can reveal.
Maginfication comes in all shapes and sizes and power, choose the one which will suit your needs first off. Always take your time viewing a coin to add to your collection and if in doubt ask an expert for advice before you "BUY"