Q. David Bowers (edited and updated by Mike Sherman): Following a pattern coinage in 1849, the double eagle or $20 gold piece made its debut in circulation in 1850. Designed by James B. Longacre, the obverse features the compact head of Liberty, her hair tied in a bun, wearing a coronet inscribed LIBERTY. Stars surround, and the date is below. The motif is similar to that used on the gold dollars of 1849-1854.
The reverse is a new motif not used elsewhere on American coinage and consists of a eagle with a squared-off shield on its breast, holding an olive branch and arrows, with ornaments to the left and right, stars and rays above, with the inscription UNITED STATES OF AMERICA, TWENTY D. surrounding. Double eagles of this type were made in large quantities from 1850 onward, although the type is sprinkled with scarce and rare dates. The New Orleans issues of 1854 and 1856 are major rarities, as are the 1861 issues with a slightly modified reverse by Anthony C. Paquet.
The type collector will have no difficulty acquiring an example of one of the more plentiful dates in Very Fine to About Uncirculated grade. Uncirculated pieces used to be scarce to rare, until the discovery of the S.S. Central America. That shipwreck yielded thousands of pieces (mostly 1856-S and 1857-S) in extremely high Uncirculated grades. While not cheap even today, they are now at least obtainable. Proofs are available for the dates 1859 through 1865, but are extremely rare.
-- Reprinted with permission from "United States Coins by Design Types - An Action Guide for the Collector and Investor" by Q. David Bowers