What this coin looks like (obverse, reverse, mint mark location, special features, etc.): The 2006-P "Reverse Proof" American Silver Eagle was the first US coin of its kind ever made. This coin was produced as part of a 3-coin silver eagle set to commemorate the 20th anniversary of the American Silver Eagle series (which started in 1986). The 3-coin set included a burnished uncirculated eagle (the first time the "W" mint mark appears on an uncirculated silver eagle) - and the set also includes a proof eagle and of course the reverse proof eagle.
The reverse proof was produced at the Philadelphia Mint using a highly innovative and technologically advanced minting process - which resulted in a coin with a frosty satin background field (like normal uncirculated silver eagles) but the details and designs have brilliant mirror-like features. This coin also bears the "P" mint mark.
Coin value chart: Typical coin prices, values and worth in USD based on grade/condition