Ron Guth:
The 1868-S Dime is a moderately scarce date that can be found in most grades up to MS64, though Mint State grades are few. In Gem condition, this date becomes a true condition-rarity. One of the best surviving examples is the Eliasberg coin; another is the PCGS MS66 example from the Eugene Gardner collection. The strike is often soft, especially on the mintmark, partly because the San Francisco Mint used the dies until they were practically worn out.
Gerry Fortin identified only a single die pair for the entire mintage of this year, plus two separate die states for the variety.