Courtesy of the Byers Collection

This is the unique and famous 1846 PROOF $2½ overstruck by an 1846 PROOF $5 Obverse Die in Copper. This spectacular Pattern Die Trial is also a Major Mint Error.

There were only a few PROOF 1846 Quarter Eagles and Half Eagles struck in Gold. There are no Patterns or Die Trials that were struck between 1840 and 1849 for any denomination other than this Unique PROOF Pattern/Mint Error struck by 1846 PROOF Gold Dies of two different denominations.

After being struck as a Proof Die Trial in copper by 1846 Proof $2½ Dies, it was overstruck by an 1846 PROOF Obverse $5 Die. In addition, it is a flipover double denomination. The overstrike by the Proof $5 Obverse Die was struck over the reverse of the $2½ design. The reverse of this overstrike, which was not struck by the reverse of the Proof $5 Die, expanded in size because it was positioned on top of a $5 Gold blank.

Not only is this unique in its own right as being a double denomination gold piece struck on a copper planchet, it is also struck by Proof Dies with two obverses. This unique and spectacular double denomination two-headed proof gold error in copper has been researched and documented in the following reference books:

Judd 110A. It is listed in Judd as the only pattern struck in 1846 and the only known pattern between 1840 and 1849. It is described as "regular Die of 1846 Quarter Eagle. Reverse overstruck with Obverse Die of 1846 (Large Date) Half Eagle. Copper-reeded edge trial piece. Unique." 

Plate coin in Pollock's United States Patterns and Related Issues, #124. "Copper-reeded edge. The reverse is overstruck using an 1846 Half Eagle Obverse Die. 

Taxay plate coin, #EP 124. 

This unique piece is also featured on coinfacts.com as the "Coin of the Week" and is described as a "unique coin [that] is both a die trial and an intentional mint error." 

Also featured on uspatterns.com and is listed as "the unique 1846 quarter eagle trial struck in copper. This famous trial is also a mint error."

After residing in several major collections it was offered in auction at the 1952 ANA (Lot #4478). Almost a decade ago it reappeared in a Bowers and Merena auction and was subsequently placed in a private collection. We recently purchased this coin and are now offering it for sale at $100,000.