The 1870-S Indian Princess Three Dollar Gold Piece ranks among the great rarities of American numismatics. It can perhaps best be described as “the coin that shouldn’t have been”. The San Francisco Mint had not struck coins of this denomination since 1860 and did not appear to ever plan to strike them again. Yet, a single 1870-S Three Dollar Gold Piece is known to exist, and another one is likely to have been struck. The reason appears to be the opening of the second San Francisco Mint and the inclusion of a full set of coins in the cornerstone of the new building.
A single example is known to exist, which is graded approximately AU with the numbers “893” scratched into the upper field of the reverse. The coin was last sold in 1982 for $687,500 and presently resides in the Harry W. Bass reference collection on display at the American Numismatic Association headquarters.