This is a unique 1966 Kennedy Half Dollar struck on a struck Washington Quarter (double denomination). It was authenticated and certified by NGC and is in gem mint state condition. It is fully struck on both the obverse and reverse with semi-prooflike fields and is possibly a SMS mint error. It is the only known Kennedy Half Dollar from 1965-1970 struck on a struck Quarter. The Kennedy Half Dollars struck during these years were on 40% Silver planchets with a weight of 11.5 grams.

The only known 1964 Kennedy Half Dollar struck on a struck Quarter dated 1965 sold for approximately 5 figures. This one-year-type was normally struck on a 90% Silver planchet with a weight of 12.5 grams.

The only known Kennedy Half Dollar dated 1971 to the present struck on a struck Quarter is a 1973-D Kennedy Half Dollar struck on a struck 1972-D Quarter. It sold for $11,750 in a recent Heritage auction. The Kennedy Half Dollars struck from 1971 to the present are on clad planchets with a weight of 11.34 grams.

These are the only three Kennedy Half Dollars struck on struck quarters known for the entire Kennedy Half Dollar series from 1964 to date. Each of these three mint errors are unique for the three different compositions in the Kennedy Half Dollar series (90% silver, 40% silver and clad).

This Kennedy Half Dollar struck on a struck Quarter shows considerable detail on the obverse including parts of IN GOD WE TRUST and parts of Washington's portrait including the neck, chin, nose and hair.

Overstrikes are featured in chapter 19 of my
NLG award winning book, World's Greatest Mint Errors.