The big key-date for the Mercury dime series is the 1916-D, a piece many numismatic experts regard as one of the most important regular-issue rarities of the 20th century. In terms of popularity and numismatic significance, the 1916-D Mercury dime is on par with the 1909-S VDB and 1914-D Lincoln cents, 1916 Standing Liberty quarter, or 1932-D and 1932-S Washington quarter.

This coin survives in far smaller numbers today than some people would probably realize. Perhaps only 10,000 exist, which is but a fraction of the 264,000 minted. It’s rare in all grades and is most commonly encountered in the circulated range of Good to Very Fine, with even these pieces easily taking a four-figure price. Mint State examples, and especially those in the Gem grades, are particularly rare. At the very least, most 1916-D Mercury dimes are well struck, so when uncirculated specimens do cross the path, it shouldn’t be very difficult to find nice examples among those.

The 1916-D Mercury dime is one of the most commonly faked 20th-century coins, and both wholesale and retail buyers should be cautious about buying raw specimens. Many fakes consist of real 1916 Philadelphia Mercury dimes with an added D mintmark. Of course, a great many others are cast counterfeits or pieces struck from crudely made and nefarious route when dealing with 1916-D Mercury dimes of any grade.