1870-S

San Francisco struck 3,000 gold dollars in 1870, the lowest San Francisco gold dollar mintage in the series. The coin is a significant rarity. The 1870-S gold dollar occupies a secondary position in San Francisco numismatic lore, overshadowed by the legendary 1870-S half dime, three-dollar piece, and silver dollar from the same year (all struck in connection with the laying of the cornerstone for the new San Francisco Mint building), but it is a scarce and desirable coin in its own right.

PCGS estimates roughly 30 to 50 survive across all grades. Most grade between Fine and Extremely Fine. Uncirculated examples are very scarce, with only a handful certified by the major grading services. An MS64 sold for $18,800 at Heritage in October 2008. The 1870-S is the most difficult San Francisco gold dollar to locate in any grade, and collectors building S-mint gold sets face it as a primary obstacle.

The coin's connection to the 1870 San Francisco Mint cornerstone ceremony adds a layer of historical interest. Several denominations struck at the San Francisco Mint in 1870 are among the rarest coins in American numismatics, and the gold dollar, while not as famous as the three-dollar piece or silver dollar from the same year, belongs to that distinguished cohort. Whether any 1870-S gold dollars were placed in the cornerstone is unknown, but the date's extreme rarity has fueled speculation for generations.