Although most commonly referred to as the "Mercury" dime, the coin does not depict the Roman messenger god. The obverse figure is a depiction of the mythological goddess Liberty wearing a Phrygian cap, a classic symbol of liberty and freedom, with its wings intended to symbolize freedom of thought. Designed by noted sculptor Adolph A. Weinman, the Winged Liberty Head dime is considered by many to be one of the most beautiful U.S. coin designs ever produced. The composition (90 percent silver, 10 percent copper) and diameter (17.9 millimeters) of the "Mercury" dime was unchanged from the Barber dime.
Weinman (who had studied under Augustus Saint-Gaudens) won a 1915 competition against two other artists for the design job, and is thought to have modeled his version of Liberty on Elsie Kachel Stevens, wife of noted poet Wallace Stevens. The reverse design, a fasces juxtaposed with an olive branch, was intended to symbolize America's readiness for war, combined with its desire for peace. The fasces symbol was later officially adopted by Benito Mussolini and his National Fascist Party, though this was the fourth party with a name invoking the fasces (in Italian: fascio) to which Mussolini had belonged. The symbol was also common in American iconography and has generally avoided any stigma associated with its usage in wartime Italy.
The 1916-D issue of only 264,000 coins is highly sought after, due largely to the fact that the overwhelming majority of the dimes struck at the Denver Mint in 1916 carried the pre-existing Barber design. Thus, the 1916-D is worth up to thousands of dollars if it is in relatively fine condition. A considerable number of common 1916 Philadelphia mint dimes have been altered with a "D" added, so buyers should be careful to purchase only from reputable dealers or to accept only sealed and graded coins.
Many coins in the "Mercury" series exhibit striking defects, most notably the fact that the line separating the two horizontal bands in the center of the fasces is often missing, in whole or in part; the 1945 issue of the Philadelphia Mint hardly ever appears with this line complete from left to right, and as a result, such coins are worth more than usual for uncirculated specimens. A valuable variety is an overdate, where 1942 was stamped over a 1941 die at the Philadelphia mint. A less obvious example from the same year is from the Denver mint.
Of particular interest to numismatics is the condition of the horizontal bands tying together the bundle on the fasces, on the coin's reverse. On well-struck examples, separation exists within the two sets of bands (known as Full Split Bands). Coins exhibiting this feature are typically valued higher than those without it.