In 2006 the extremely popular American silver eagle celebrated its 20th year of the series. Many silver eagle collectors own the regular Brilliant Uncirculated issues, but the most beautiful and desirable form of these precious coins are the spectacularly minted proof issues. More than 10 million Uncirculated issues were struck in 2006, but just 1.1 million proofs were output. Each one ounce .999 silver dollar showcases superb, deep-etched frosted engravings and dazzling mirror backgrounds.