Collectible coins can encompass a wide variety of types, including commemorative issues, historical coins, and patterns or trial coins. In the context of the United States, the Two and a Half Dollar coin, also known as the quarter eagle, was minted to signify a quarter of a gold eagle's value. The 1857 pattern coins produced in Philadelphia represent experimental designs that were not intended for circulation, showcasing the Mint's attempts to refine coinage before official release. These patterns can be highly sought after by collectors due to their rarity and historical significance.

Item Denomination Series Year Mint
United States of America 1857 Philadelphia Patterns & Trial Coins $2.50 $2.50 (Two and a Half Dollars) Patterns & Trial Coins 1857 Philadelphia