This was the last Washington quarter issued for commerce to boast 90% silver content. After 1964, the U.S. Mint phased out silver coinage in circulation. Over the years as the value of silver has risen — sometimes dramatically — many silver-rich coins like these were lost to melts. These 1964 quarters were never used in commerce and are as nice as the day they left the Mint. Our choice of mintmark. Limit 5 per household.