What Is A Proof Coin?
To completely understand what a proof coin is, you need to know a little bit about the coin minting process. To see a full explanation of coin minting, see our blog post about it here: http://blog.goldeneaglecoin.com/silver-coins-minted/
Up until 2008, when a coin die was created, it was hand carved onto a larger version of the die (18 inches roughly) called a galvano. This larger format allowed engravers to create minute details into the design. After the design is created, it is reduced down into the actual size of the coin that it is going to stamp with a reduction lathe.
Once the actual die is created, the entire die is polished to a high sheen and a proof is stamped. This means they take a blank planchet and stamp it once to test out how the die stamped worked. These first few coins are proof quality because the die is still highly polished. This creates a beautiful mirror-like quality to the coin as well as having all of the detail intact. The more the die is used, the more the die will wear down with each stamping losing a bit of its detail.
Because these first proof coins were so sought after, the U.S. Mint decided to create more proof coins specifically for coin collectors. These dies are highly polished to strike mirror-like finishes onto the coins. In some cases, the dies are set to strike with higher force or the coins are struck twice to ensure that the proof coins have a high level of detail and finish.