Based on the provided information and general numismatic knowledge, the coin featuring President John F. Kennedy is a half dollar, not a dollar. This is a common point of confusion. The value of a Kennedy half dollar depends almost entirely on its year of issue, as this determines its silver content and overall rarity.
The most valuable circulating Kennedy half dollars are from 1964. These coins are composed of 90% silver, and their base value is tied to the current spot price of silver. This "melt value" is typically several dollars.
From 1965 to 1970, the composition of the Kennedy half dollar was changed to a 40% silver-clad composition. While still valuable for their silver content, they are worth significantly less than the 1964 issue. Their base value is also determined by the fluctuating price of silver.
Kennedy half dollars minted for circulation from 1971 to the present day contain no silver. They are made of a copper-nickel clad composition and are generally only worth their face value of 50 cents unless they are in pristine, uncirculated condition or are special collector-only issues. The U.S. Mint has produced special silver proof versions for collectors in recent years, which carry a premium value.
Ultimately, the exact worth of any specific Kennedy half dollar is determined by its date, mint mark, silver content, and physical condition. Coins in better condition or those that are special collector proofs will command higher prices than circulated examples.
