If it’s a Washington Quarter (or similar) from 1964 or earlier, then it’s composed of 90% silver and 10% copper, with a total weight of 6.25 grams.
• In that composition, it contains approximately 0.1808 troy ounces of pure silver.
• Using the current silver price (~US $50.82 per troy ounce according to the source), the melt value comes out to about US $9.19 for that coin.