Q. David Bowers (edited and updated by Mike Sherman): Christian Gobrecht’s Coronet design, also called the Liberty Head type, made its appearance in the half eagle series in 1839. The obverse depicts a female head facing left, her hair tied in a bun secured by a string of beads, wearing a coronet inscribed LIBERTY, stars surrounding, with the date below. The reverse shows an eagle with a shield on its breast, perched on an olive branch and holding three arrows. The inscription UNITED STATES OF AMERICA, FIVE D. surrounds.
Issues of 1839 and some of 1840 measure 22.5 mm in diameter, and are sometimes referred to as “broad mill” pieces, whereas later issues measure 21.6 mm. The earlier issues showed smaller lettering on the reverse and a smaller date. By the mid-1840s, most issues now featured larger reverse lettering and a larger date. Some dates, notably 1842, showed both styles.
Coinage was accomplished at the Philadelphia Mint on a continuous basis during the entire span. Additional pieces were made from time to time at Charlotte, Dahlonega, New Orleans, and San Francisco. In general, Charlotte and Dahlonega pieces are scarce. The prime rarity in this series is the 1854-S, struck during the first year of operation at the San Francisco Mint, a coin of which just 268 were made and of which only three are known to exist today.
The type collector will have no problem acquiring one of the more plentiful dates in any desired grade from Very Fine through the lower ranges of Uncirculated. Once you go above MS64, the story changes and you’re looking at a very rare item. Proofs were made in limited quantities, and are likewise very rare.
In 1866, the Liberty Half Eagle was modified by adding the motto IN GOD WE TRUST on a ribbon above the eagle on the reverse. Apart from this, the motif with Liberty Head on the obverse and perched eagle on the reverse is the same used in earlier years. Mintage of the with-motto style was continuous at the Philadelphia Mint, with additional coins being made at San Francisco, Carson City, New Orleans and in 1906 and 1907, at the new Denver Mint. Combined with the earlier “no motto” style, the Liberty Half eagle is the only coin to be struck at all seven of the “traditional” U.S. mints.
Due to the high original mintages of many issues (particularly after 1880), obtaining a “with motto” half eagle should present no difficulties in any grade, up to and including MS-65. MS-66s are available, though scarcer. Above MS-66, the supply thins considerably. As a date, the only “show stopper” is the Philadelphia issue of 1875. With an original mintage of only 200 pieces, fewer than five have survived. Philadelphia minted Proofs in all years, and are rare.
-- Reprinted with permission from "United States Coins by Design Types - An Action Guide for the Collector and Investor" by Q. David Bowers