The copper coins, known as the "silver center cent" and the "Birch cent," are expected to sell for about a half-million dollars each, and were made during the early days of the United States Mint.
The silver center cent was minted at a time when the melt value of a coin was expected to match the face value, and in an effort to keep the copper coin from weighing too much, a silver center was added to match that value, according to Wikipedia.
The Professional Coin Grading Society (PCGS) says that the Birch cents are named for Robert Birch, the man responsible for engraving the large copper patterns used in the minting process. Birch cents have sold for well over $1 million by themselves in previous auctions.
Eric Bradley of Heritage Auctions, which is holding the sale, calls them classic American rarities that represent America's early attempts to distance itself from Britain.
for more features.