Collectible coins encompass a diverse range of numismatic items, including historical pieces, commemorative coins, and currency errors. In the United States, the 25-cent quarter is a popular collectible, often sought after for its designs and historical significance. California Fractional Gold coins, issued in the mid-19th century, represent a unique category of collectible gold coins, often used for everyday transactions during the California Gold Rush. The designation "18721 Unknown" may refer to a specific coin or cataloging entry but lacks sufficient context for detailed analysis.

Item Denomination Series Year Mint
18721-- (Unknown) California Fractional Gold 25¢ (Twenty Five Cents, Quarter) California Fractional Gold 18721 Unknown