An assessment of the value of a 1971 Kennedy half dollar requires a crucial clarification regarding its metallic composition. The premise of a "1971 Kennedy silver half dollar" is generally incorrect for coins intended for circulation. The United States Mint ceased using a 40% silver composition for circulating Kennedy half dollars after 1970. Consequently, all 1971-dated half dollars struck for general circulation at the Philadelphia (no mint mark) and Denver ("D" mint mark) Mints are composed of a copper-nickel clad alloy, containing no silver.
Due to their copper-nickel composition and the very high mintage figures for that year, a standard 1971 or 1971-D Kennedy half dollar found in circulation is typically worth only its face value of 50 cents. Their numismatic or collectible value is minimal unless they are in pristine, uncirculated condition. A certified, high-grade uncirculated example may command a modest premium of a few dollars among collectors. The 1971-S proof versions, struck at the San Francisco Mint for collector sets, were also made of copper-nickel clad and are similarly valued at a few dollars.
There is, however, an exceptionally rare and valuable exception. A very small number of 1971-D half dollars are known to have been mistakenly struck on 40% silver planchets (coin blanks) leftover from 1970. These are considered transitional error coins and are highly sought after by collectors, commanding values in the thousands of dollars. Such an error coin can be distinguished from its common counterpart by its weight (a 40% silver planchet weighs 11.5 grams, while a copper-nickel clad one weighs 11.34 grams) and the presence of a silver-colored edge, as opposed to the copper-colored band visible on a clad coin's edge. In summary, while virtually all 1971 Kennedy half dollars are worth face value, the discovery of a legitimate transitional silver error would be a significant numismatic find. The provided source titles from pricing guides like Greysheet confirm that this is a coin with established values, but do not contain the specific data to detail them further.
