Pure silver comes in 1 ounce, 10 ounce, 100 ounce and 1000 ounce bars. America, Canada and China also make pure silver specialty coins. American dimes, quarters and half-dollars from 1964 and earlier also contain 90% silver. Rare coins have a premium and common date. Coins are traded for their silver value. Half dollars from 1965-1970 are 40% silver and are bought accordingly.