Ron Guth: The first of the new gold dollars was a small coin, roughly half an inch in diameter, featuring a bust of Liberty facing left (the same design that was utilized on the $20 gold piece the next year). Thanks to the influx of gold from California, the mintage of the gold dollar was substantial, and far higher than any other gold coin previously issued by the U.S. Mint (except for the 1847 Eagle). Between 1849 and 1854, Gold Dollars were struck at the Philadelphia, New Orleans, San Francisco, Dahlonega (GA), and Charlotte (NC) mints. Philadelphia was the biggest producer of Gold Dollar, with most of the gold coming from California. Dahlonega and Charlotte relied on local supplies of gold, so their output was vastly smaller in comparison.
A complete date set of Gold Dollars can be completed with ease. A date and mintmark set is much more challenging because of the scarcity (and rarity) of the afore-mentioned C- and D-Mint Gold Dollars. The "big" coin in this series is the 1849-C Open Wreath, a variety that has shorter sprigs on either side of the reverse (the Closed Wreath variety was used on some 1849 and all 1850-1854 Type One Gold Dollars).
Several dates in this series are available in superb condition, but all of the branch mint coins are scarce to rare in high grade, some prohibitively so.
In 1854, the diameter of the Gold Dollar was enlarged from 13 mm to 15 mm, coincidental with a change in the design.