Fine. What did it weigh? If you do not remember, then get it weighed again and this time, write down the weight as the "weight" is the first determining factor in whether or not it is silver. After that, a specific gravity test would be performed. The specific gravity test needs to be done by a reputable individual and not just the guy next door. Well, unless he's a reputable numismatist qualified to perform accurate specific gravity tests in which case, it would be ok. Look, if its an authentic 1965 90% Silver Quarter, it would definitely be worth ANY effort put into validating its composition and at some point in time, if you want to really reap the rewards of such a find, you'll have to trust someone somewhere along the line or at the very minimum, perform the tasks tat those folks on this forum have requested. IF the coin is not "professionally" evaluated, then selling it will probably net you .20 cents.