Its original mintage of just 30 Proofs meant that this issue was very rare the day it was struck. With normal attrition, there are now 13-15 Proof 1879 half eagles known and this figure includes a number of pieces which are impounded in museum collections. Most grade in the PR63 to 64 range and seldom show more than cursory contrast.
This piece, from the famous Bass Collection and designated as such on the insert by PCGS, is clearly among the finest known. The highly reflective surfaces are touched with rich orange-gold color which turns to a vivid lilac hue at the peripheries. This color is natural (albeit unusual) and it was the same when it was last sold in late 2000. There are a few light lines in the left field which narrowly remove it from a Gem grade.
Goldberg 2/11: 2133, graded PCGS PR64+DCAM, sold for $43,700 and is the only relevant comparable.
A lovely example of a truly rare Proof half eagle.
Ex Bass IV (Bowers and Merena 11/00): 534, where it sold for $21,850.