A numismatist is an individual who collects or sells coins. Some numismatists collect coins for the value of their materials, while others hunt rare coins from a particular era or location.
Coin collecting once was an activity that only the wealthy could participate in, which is why it still is known as "the hobby of kings." The hobby became popular in the United States in the mid-19th century, a period that coincided with the California Gold Rush and the production of new federal coins. Coin collecting attracted new numismatists when the U.S. Mint began releasing commemorative coins in the 1930s.