All too often, numismatists tend to lump coins into three categories: common, better and rare. Common coins are the most available issues of a given type—and they’re the lowest priced. Better dates command some kind of premium, but can still be found with some regularity. A rare date, meanwhile, is infrequently seen and is dramatically more expensive.

To use specifics coins as example, dates like 1881-S and 1884-O would be considered common in the Morgan dollar series. They are readily available in grades from well worn to Gem Uncirculated. If someone placed an order for “generic” Morgan dollars, a dealer would have no qualms about using these two dates.

An example of a better date Morgan would be an 1898-S. This coin is tougher to find in circulated grades and sells for many times the common price in Uncirculated. It’s not exactly rare—1898-S Morgans do appear on the market with regularity—but it’s universally acknowledged that it’s a better date. A low-grade Uncirculated coin, to use actual numbers, sells for $150-$300 versus $40-$60 for a common date.

Rare dates are worth a premium in all grades and are extremely difficult to source. For the Morgan Silver Dollar series, the 1893-S would be an excellent version of a rare date. Even low-grade examples sell for $1000+ and an Uncirculated piece will set you back tens of thousands. In MS 65, this date is a six-figure item. To call this coin “better” would not quite do it justice, hence the term “rare.”

This brings us to coins that represent the best value: those that are actually better but somehow get lumped into the common category. Many of these dates are legitimately scarce and challenging to find, yet for some reason they haven’t received the proper recognition. Why would coins like this get overlooked? Perhaps a price guide has been underreporting the coin’s true scarcity, maybe it wasn’t included in a large marketer’s promotion, or sometimes coins simply slip through the cracks.

For example, the 1913-D $20 Saint Gaudens Double Eagle is at least 75x-100x rarer than the most common date. It’s easy to buy hundreds if not thousands of generic date “Saints” but finding a dozen 1913-Ds can be quite tricky. Yet, this coin commands little or no premium until you get to high grades. Why? No large marketing house has promoted the series and it’s an expensive series to collect. If there were more numismatists targeting the $20 Saint Gaudens series by date, they would eventually realize how hard it is to find a 1913-D (and would bolster the price accordingly).