Ron Guth:
The mintage of the 1851 Dime is slightly more than half that of the 1850. This makes the 1851 Dime slightly more rare, but it does not command much of a premium over the normal type coins until well into the Mint State grades. Most Mint State examples are either MS63 or MS64, with but a few examples above and below. Gems are truly scarce and any 1851 Dime in MS66 or MS67 is an extreme rarity. The finest example is the Eliasberg PCGS MS67 sold in 2013 for $20,563. The 1851 Dime normally shows weakness on some of the stars and denticles and in the area of the first A in AMERICA on the reverse; it is doubtful if a fully struck example exists.