are 50 cent pieces pure silver

[Ferreira]

Based on the information provided, United States 50-cent pieces, or half dollars, are not and have never been made of pure silver. Pure silver is too soft and malleable for use in circulating currency, so it has always been alloyed with other metals to increase its durability.

The silver content in half dollars has varied significantly over time. For many years, up to and including 1964, half dollars such as the Barber, Walking Liberty, Franklin, and the 1964 Kennedy half dollar had a composition of 90% silver and 10% copper. These coins are widely collected for their high precious metal content.

A significant change occurred in 1965. From 1965 through 1970, the composition of the Kennedy half dollar was altered to a 40% silver clad composition. Following this period, another change was made. Beginning in 1971, all circulating half dollars minted for general use contain no silver at all; they are instead made from a copper-nickel clad composition. Therefore, while many older 50-cent pieces are valued for their substantial silver content, none of them are pure silver.