Ron Guth: In 1859, the Mint tweaked the appearance of the Tree-Cent Silver by removing one of the outlines surrounding the star, changing the shape of the lettering, and reducing the size of the digits in the date. The mintage in 1859 dropped significantly to less than a fourth of the previous year. Nonetheless, this is a relatively common date in all grades, up to and including MS66. This date suffers from clashmarks despite the redesign, but not to the degree seen on previous dates.
PCGS has certified hundreds of Mint State examples of this date, the finest of which are three PCGS MS67s.