Ron Guth:
The 1859-O Dime is a relatively common coin that can be found with ease in most grades, up to (and including) MS66. This is a marked, upward shift from previous years and the increased surival rate of quality coins may be the result of a rise in the popularity of coin collecting in America. This is reflected in the existence of an NGC MS68 which represents the single finest example known of this date.
Researcher Jerry Fortin has identified five different die varieties for this date, all of identical rarity. Mintmarks come in either Medium or Large sizes.