The standard reference works on US commemorative coins generally list July 3, 1925 as the opening date for sales of the Stone Mountain Memorial Half Dollar. The date was put out by the Stone Mountain Confederate Monumental Association and has been included in references since 1938 when published in David Bullowa's
The Commemorative Coinage of the United States, 1892-1938 volume.
There are, however, contemporary accounts that suggest earlier dates for the coin's availability.
For example,
The Washington Times reported in its June 5, 1925 edition that the Association reported that the availability date had been changed, and that the coins would be available from the Federal Reserve Bank in Richmond to banks in the District of Columbia beginning on June 13, 1925. Other newspaper reports in June also indicated the coins were available prior to July 3rd.
The Winona Times of Winona, Mississippi, in its May 29, 1925 issue, reported that sales of the 1925 Stone Mountain Memorial Half Dollar would begin on June 3, 1925 . The notice highlighted the significance of the date, as it is the birth date of Jefferson Davis, the Confederate States President from November 6, 1861 (elected; February 22, 1862 inaugurated) through May 5, 1865.
(Related Side Note: the first day of striking for the half dollar was January 21, 1925 - the 101st anniversary of General "Stonewall" Jackson's birth.)Davis was originally considered for depiction on the half dollar as the third horseback figure, along with Generals Robert E. Lee and Stonewall Jackson, but was dropped from the design in consideration of space limitations and overall aesthetics. Davis was depicted, however, on the Founder's medals by Gutzon Borglum and Augustus Lukeman. (See:
1925 Stone Mountain Cousins - The Lukeman Medals.)
So, while some organizations may have officially kicked off sales based on the Association's original July 3, 1925 launch date, others appear to have gotten a jump and launched sales in June.
1925 Stone Mountain Memorial Half Dollar
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For other of my posts about commemorative coins and medals, including much more about the Stone Mountain coin, see:
Commems Collection.