PCGS graders have recognized the scarcity of many Mercury dimes that display full band details on the reverse of the coin. Hence, Mercury dimes displaying full central band details on the reverse will receive the Full Band designation by PCGS.
Some Mercury dimes such as the 1918-D are extremely scarce with the full band details. In fact, a 1918-D Mercury dime graded PCGS MS66 will usually bring a bit over $1,000 in the market. The same coin graded by PCGS MS66 but with the Full Band designation will bring in excess of $100,000 in the market!
Coins with full split band details usually indicate that the coins were struck from a fresh and well-defined pair of coin dies and under the correct pressure. Mercury dimes which lack full split band details usually indicate that the coin dies striking the reverse of the coin had worn out on the central band details. Since one of the highest portions of the coin's reverse design is the central bands, this area has the tendency to wear out the quickest.
Consequently, Mercury dimes with full split band details are extremely coveted by astute collectors. These collectors wish to own examples of the best-defined and best-struck Mercury dimes in existence.
To PCGS graders, a Mercury dime with full band details will have fully separated horizontal bands on the central part of the fasces (the bundle of rods on the reverse). In addition, there can be no interruption on the trough (depression) of the bands due to strike, contact, planchet problems or any other damage, whether mint caused or not, if the coin is to obtain the PCGS Full Band designation.
Although the central bands must be fully separated with no interruption, it is not necessary to have full roundness to the bands – the so-called “McDonald's Arches” that are sometimes referred to as Full Split or Full Rounded Bands.
Above is an image of a 1941-D Mercury dime with interrupted and very weak details on the splitting of the central bands. This coin would not receive the Full Bands designation by PCGS.