Estimated grade. Sold in Stack's Auction of Garrett / Hopkins University, Mar. 1976
P. Scott Rubin: The 1875 Proof Half Eagle is one of the rarest and most desired coins in a denomination that hosts some of the rarest and most desired coins in all U.S. coinage. This coin offers the rare opportunity to acquire an extremely rare date and denomination issue in superb condition. With a mintage of only 20 Proof 1875 Half Eagles struck and only 200 circulation strikes issued with the same date, makes this coin one of the lowest mintage in all U.S. numismatics.
Because of its low mintage this has always been a much desired coin. Collectors at the time of issue saved the Proof specimens in the few gold coin collections being built in the late 1870’s where completeness was the goal. This seems to show how few Collectors at the time strived for such collections of Gold coinage and also explains why so few of the 200 circulation strikes were saved in the year of issue. The highest grade seen for a circulation strike is About Uncirculated-58.
It is believed that as many as eleven Proof Half Eagles survive of which three are in Institutional Collections. This is a high survival rate but makes sense as explained above. There also seem to be less than 10 circulation strikes known, showing just how rare the 1875 Half Eagle really is.