Editor’s Note: From the Heritage Galleries auction listing:

1891 $5 --Triple Struck with Reverse Rotation--PR64 Ultra Cameo NGC. This rare proof half eagle was struck at least three times by the dies. Of course, all proof Liberty fives were multiple struck, to bring out complete definition. What makes the present piece an error is that the hammer (reverse) die was apparently loose, and rotated a couple of degrees between strikes. The anvil (obverse) was stationary. As a result, the obverse shows no evidence of a multiple strike, but the reverse has faint rotated impressions from the prior two strikes. These are most apparent above the eagle’s right (facing) shoulder, and southwest of the eagle’s beak. For the final strike, the dies were close to medal turn. The devices are fully frosted, and contrast greatly with the darkly mirrored fields. Hair-thin field imperfections near the date, star 10, and the neck curls are all that limit the grade. A mere 53 proofs were struck, and perhaps half that number have survived. The NGC and PCGS population data are undoubtedly inflated by resubmissions over the past 22 years. Census: 4 in 64 Ultra Cameo, 9 finer (1/08).