Which Jefferson nickel coins are difficult to find?
Jefferson nickel coins that are difficult to find include those with special mint marks, produced during specific years or with unique errors. For instance, Jefferson nickels minted during World War II, known as 'war nickels', are rare due to their unique composition of silver, copper, and manganese. Additionally, coins with minting errors or those from limited production runs, such as the 1950-D Jefferson nickel with a missing mint mark, are also highly sought-after by collectors.