1915-S Panama-Pacific Exposition $50. Octagonal. MS-64 (PCGS). CAC. This is a gorgeous coin, the type impressive in all regards and the level of surface preservation finer than that seen in most survivors. Vibrant golden-wheat patina greets the viewer across both sides, accented by subtle hints of powder blue and lemon-yellow. Smooth and inviting in hand with intense mint luster and satin to softly frosted texture throughout. Just 43 coins have been certified finer by PCGS.One of five coin issues struck in association with the Panama-Pacific International Exposition celebrating the rebirth of San Francisco and the opening of the Panama Canal, the octagonal $50 gold shares the same basic design as its round counterpart, but features extra outer borders on both sides, each with eight dolphins that symbolize the uninterrupted waterway created by the opening of the Panama Canal.The San Francisco Mint struck 1,500 examples of each Panama-Pacific $50 for sale at the Exposition. Due to their different shape and the addition of the symbolic dolphin border, the Octagonal pieces proved more popular with contemporary buyers. In truth, sales for both were disappointing, the original asking price of $100/coin proving too steep for most contemporary Americans. Attempts to increase sales by discounting the price of the $50s when offered as part of sets with the smaller denomination Panama-Pacific coins did little to improve the situation, and in the end most examples of both varieties were destroyed by the Mint as unsold. The distribution for the octagonal proved to be just 645 pieces, greater than the 483 coins for its round counterpart, but still a small total that explains the scarcity of survivors in todays market. Eagerly sought in all grades, we anticipate keen bidder interest in this superior Choice example.