1873-S Liberty Head Half Eagle. AU-50 (NGC). A sharply defined and significant AU to represent this scarce Frontier era issue. Pale yellow-gold patina blankets surfaces that reveal ample satin luster as the coin rotates under a light. Produced to the extent of just 31,000 pieces, and suffering a high rate of attrition through circulation, the 1873-S is an elusive half eagle in all grades, especially those above EF.