An example of the 1965 Martha Washington half dollar, J2132/P2083 has been discovered struck on a copper-nickel clad quarter planchet.
The only other examples of this rare pattern are the two on a full cupro-nickel clad half dollar planchet and 6 pieces struck in silver-clad J2134/P2083 embedded in 2 blocks of lucite which reside in the Smithsonian. To view one of these blocks, click here.
These dies serve as the Mint's all-purpose dies and are given out to outside companies by the mint for testing. It is, therefore, not known whether or not this mint error was made inside or outside the Mint.
The illustrated piece, struck from heavily clashed dies, sold in Heritage 3/2003 sale for $29,900 and resold for $21,850 in Heritage 2004 ANA sale.
Photo courtesy of Heritage.