Here are a few factors that can affect the value of a 1951 half dollar:
Condition: The condition of a coin can significantly impact its value. Coins that are well-preserved and have few scratches or marks will generally be worth more than coins that are worn or damaged.
Rarity: Some 1951 half dollars are rarer than others. This can be due to a variety of factors, such as the number of coins minted that year or the condition of the coins that survived. Rarer coins will generally be worth more than common coins.
Mint mark: The mint mark on a coin can also affect its value. Coins that were minted at certain mints, such as the Philadelphia Mint or the Denver Mint, can be more valuable than coins that were minted at other mints.
Errors or varieties: Coins with errors or varieties can be worth more than regular coins. Errors can occur during the minting process, such as a misaligned die or a missing mint mark. Varieties are minor changes to the coin's design that can occur over time.
If you have a 1951 half dollar that you believe may be valuable, it is a good idea to have it appraised by a professional coin dealer or numismatist. They will be able to accurately assess the value of your coin based on its condition, rarity, mint mark, and any errors or varieties.