White Metal. Obverse: rusted 1806 Pointed 6 Half Dollar die used previously on the O-123 and O-124 varieties, then believed discarded or sold by the Mint for scrap. This die is now part of the American Numismatic Society’s collection.
Reverse: rusted die for a United States embossed 12C envelope stamp featuring a portrait of Henry Clay.
Others are known with a plain reverse (see Pollock-6145). Pollock-6155 is a uniface impression in White Metal of the Henry Clay stamp. Abe Kosoff believed David Proskey made these pieces.[1]
[1] Abe Kosoff, An Illustrated History of United States Coins: Depicting the Proposed Designs as Well as the Accepted Types (Abe Kosoff, 1962).