Collectible coins can encompass a wide range of types, including patterns, which are often test strikes or experimental designs that were never released for circulation. The 1863 Philadelphia pattern coins, particularly those related to the United States, are significant due to their rarity and historical context. These patterns were produced during a time of transition in American coinage, often featuring unique designs that differ from standard issues. The PH10c designation typically refers to a specific type of pattern coin within the series, sought after by numismatists for its aesthetic and historical value.