The 1856-O double eagle is one of the great rarities of the Liberty Head series. There are thought to be fewer than 25 coins known in all grades. The known coins range in grade from polished Very Fine to Specimen-63. Most collectors of double eagles have given up on this date as the starting price for an attractive example begins in the six figures. The Smithsonian contains two examples. Of the small number of coins known in About Uncirculated condition, most are at least partially prooflike. The collecting of gold coins by mintmark did not start in earnest until decades after the 1856-O double eagles were struck. Today, the issue is considered a “classic.” Note: This coin is included among the 100 Greatest U.S. Coins (Garrett and Guth 2005).