Circulated or Uncirculated? Proof or No Proof?
Numismatic coins fall into one of two basic categories for quality: circulated and uncirculated. Circulated coins exhibit wear, whereas uncirculated coins do not. Uncirculated coins tend to be more valuable, causing investors and serious collectors to focus their efforts on acquiring the uncirculated alone. Numismatists are trained to identify coins as circulated or uncirculated.
“Proof” is another key concept in coin grading. A proof coin is one that is struck at least twice with specially prepared dies and planchets, and under higher-than-normal pressure to ensure a full, sharp strike. Proof coins are more scarce and tend to be more valuable than other rare coins, drawing special attention from investors and collectors. Some proof coins are deemed circulated because they have been held by investors and collectors.
Many proofs are also cameo proofs, meaning the area of the die that creates the coin background, or field, is highly polished, while the area of the die used to create the raise images is sandblasted. The end result is a coin with a mirror-like field and a frosty devise — a highly coveted effect for any collection.