The 1915-S Panama-Pacific Half Dollar was authorized by an Act of Congress on June 16, 1915 as a fund-raiser for the International Exhibition held in San Francisco, California celebrating the opening of the Panama-Pacific Canal. The Act authorized a mintage of 200,000 pieces, but only 60,030 were struck. In addition to the regular silver pieces just mentioned, a small number of examples in gold, silver, and copper were struck at the Philadelphia Mint before the "S" mintmark was added to the dies. No record of any Proof strikings exist, but Breen repeats the rumor of the existence of two Satin Finish Proofs, both with mintmarks.
The Panama-Pacific Half Dollars were sold individually for $1.00 (see the image of the original sales envelope below), or as part of complete sets (containing a Pan-Pac Half Dollar, a Pan-Pac $1.00, a Pan-Pac $2.50, a Pan-Pac $50 Round, and a Pan-Pac $50 Octagonal), or as part of complete double-sets (containing two each of the Pan-Pac Half Dollar, the Pan-Pac $1.00, the Pan-Pac $2.50, the Pan-Pac $50 Round, and the Pan-Pac $50 Octagonal).
Of the original mintage of 60,030 pieces, 30 were set aside for assay purposes and 32,866 unsold coins were destroyed, leaving a net mintage of 27,134.
Many Uncirculated examples exist, with the most common grade being MS-64. Gem examples are readily available.
Sources and/or recommended reading:
"Walter Breen's Complete Encyclopedia of U.S. and Colonial Coins" by Walter Breen
After the Columbian Exposistion half dollars of 1892 and 1893, the Isabella quarter in 1893 and the Lafayette dollar in 1900, the next silver commemorative to be struck was the 1915-S Panama-Pacific half dollar. The Pan-Pac half was struck in San Francisco in conjunction with the Panama-Pacific International Exposition which was held in San Francisco in 1915 to celebrate the 1914 opening of the Panama Canal and also the "rebirth" of the city after the devastating earthquake of 1906. A gold dollar, gold $2.5 and two types of $50 gold "slugs were also struck.
The original issue price for the half dollar was $1 or "6 pieces for $5." The halves were also sold in sets with the gold coins, with set options being three, four, five, or ten coins. The complete five piece set in a copper frame was sold for $200. The original distribution of the silver half dollars amounted to 27,134 coins.
Today, the Pan-Pac silver half dollar is considered one of the most important issues in the silver commemorative series. It is also one of the scarcer issues in Gem condition. The grades of the survivors are well distributed. Though there are a number of lightly circulated pieces known, most survivors are mint state. This is quite logical as they were sold at a premium to face value at the time of issue. The most frequently encountered grade is MS64, then MS63, followed by MS65. There are a number of Superb Gem MS66 survivors and some MS67 pieces.
The typical Pan-Pac half has somewhat frosty luster. Marks are usually not much of a problem, but strike can be. Look at the eagle's breast feathers. Some specimens have soft, indistinct detail and some (more rarely) have full feather detail. Obviously the full strikes are most desireable. The other issue with Pan-Pac halves is eye appeal. This coin often has toning. Sometimes, the toning is quite attractive, sometimes it's just neutral, and sometimes is downright hideous. So obviously you should avoid hideous eye appeal!!!!! This is a beautiful and important 20th Century commemorative issue and one of my favorites in the entire silver commemorative series.