The rarity of a 1971 silver half dollar stems from its composition and intended purpose, as the vast majority of half dollars produced that year were not made of silver. The standard 1971 Kennedy half dollars intended for general circulation were composed of a copper-nickel clad alloy, and hundreds of millions were minted, making them very common.
However, the United States Mint did produce special versions for collectors that contained silver. These rare variants are the 1971-S half dollars, which were struck at the San Francisco Mint. These coins were specifically minted on 40% silver planchets and were sold directly to collectors in special sets, such as Proof sets and Uncirculated Mint sets. They were never intended for circulation, and their production numbers were significantly lower than their copper-nickel counterparts, which is the primary source of their rarity.
An even rarer type of 1971 silver half dollar is a transitional error. This would be a coin from the Denver (1971-D) or Philadelphia (1971 with no mint mark) mints that was accidentally struck on a leftover 40% silver planchet from 1970. Such an error coin would be exceedingly rare and valuable because all coins from those mints were supposed to be copper-nickel clad. Therefore, the value and rarity of a 1971 half dollar are almost entirely determined by whether it is one of these special silver issues rather than a standard circulating coin.
