The 90% Quarters (BU) is a brilliant uncirculated coin product offered by the United States Mint. It consists of a quarter-dollar coin that has been struck on specially burnished blanks, resulting in a stunning mirror-like finish on both sides. These coins are produced with a composition of 90% silver and 10% copper, giving them a unique and attractive appearance. The 90% Quarters (BU) are highly sought after by coin collectors and precious metal enthusiasts alike, as they combine the beauty of a brilliant uncirculated coin with the intrinsic value of silver content.