The Panama-Pacific International Exposition was commemorated with distinctive half dollars, gold dollars, quarter eagle $2.50 pieces, and two types of gold $50 pieces — octagonal and round. While 1,500 coins of each $50 shape were minted, the octagonal piece, which harkened back to octagonal $50 Gold Rush slugs, proved more popular with buyers than the round pieces.
Mint records show that 864 octagonal pieces and 1,027 round pieces went unsold and were melted. That gave the round piece a net mintage of just 483 pieces, making it the rarest U.S. commemorative coin.
The coin is shown for just a few seconds during the show, a single coin in a Zerbe case. In Commemorative Coins of the United States: A Complete Encyclopedia, author Q. David Bowers writes, “A complete set consisting of one each of the half dollar, gold dollar, quarter eagle, and choice of $50 (round or octagonal) could be had for $100, the same price asked for a single $50 coin, so it seems reasonable to assume that most $50 pieces were sold as parts of sets.”
The round $50 is a major rarity today, worth considerably more than its $6,000 value in 1969. In 2010, Stack’s Bowers Galleries sold a Professional Coin Grading Service Mint State 66 example for $281,750.
The episode can be viewed online free at Hulu.