10 Dollars - Charles III World's Purest Bullion

The "five nines" (.99999) fineness designation is not purely nominal — achieving it requires a refining process that removes virtually all trace elements, including the copper and silver impurities that give standard .9999 gold its faint color variation. Very few mints worldwide maintain the infrastructure to certify this standard consistently, with the Royal Canadian Mint being the most established producer of five-nines gold since the 1990s.