Ron Guth:
In 1858, production of Quarter Dollars at the New Orleans Mint dropped to less than half that of the previous year. Nonetheless, the mintage of the 1858-O Quarter Dollar remained over 500,000 coins. This date is a litrle bit tougher to find than some other contemporary O-Mint dates, but it isn't until the grades approach the About Uncirculated level that the search becomes serious. Mint State examples are downright rare, with the finest being a single PCGS MS64+.
The strike quality on 1858-O Quarters is above-average for a New Orleans Mint product, though it is probably impossible to find an example with full radial lines in all the stars and full denticles on both sides.