In the United States, all dimes, quarters, half dollars and dollar coins produced prior to 1965 were minted of an alloy that was comprised of 90% silver. These coins were in everyday circulation and used for daily transactions.
Any combination of half dollars, quarters and dimes minted in 1964 or earlier that add up to $1 dollar face value contain roughly .715 troy ounces of silver bullion. Peace Dollars, Morgan Dollars and earlier one-dollar coins contain .7736 troy ounce of silver. The remaining weight is comprised of 10% copper.
From 1965 until 1970, Kennedy half dollar coins were minted of an alloy containing 40% silver. Beginning in 1971, these half dollar coins were minted entirely of non-precious metals, primarily nickel and copper.
During World War 2, various raw materials were being rationed for the war effort, including nickel which was used in armor plating. From mid-1942 to 1945, the Jefferson Nickel was minted from an alloy containing 35% silver. These nickels are often referred to as “War Nickels” because the years’ of their minting correspond to the second world war.