Roosevelt and Mercury Dimes, Washington Quarters, and Walking Liberty Franklin and Kennedy Half-Dollars minted in 1964 and earlier are 90% silver. The value of most circulated coins minted in the 1920′s through 1964 is primarily from their silver content. Remember, this is for the most common material.
Silver coins issued until 1964 were made with 90% silver content. These coins were Half Dollars, Quarters and Dimes as well as Silver Dollars until 1935.
Quarters and dimes would contain no silver while half dollars would be made..to eliminate silver from U.S. quarters and dimes, and reduce the silver content.
Maybe you already know this, but I will tell you anyway. Before 1965, US quarters were made of 90 percent silver. That means that due to the silver alone it would be worth about $3.50 (depending on silver prices). After 1964, the quarter is just made of nickel and copper and worth just 25 cents.