uses a numeric grade to succinctly describe a problem-free coin's condition. Certain coins, however, require a more nuanced description of their condition and appearance. For these coins, NGC
graders follow the numeric grade with a range of designations, often called "Strike Characters."Read More: Learn Grading
Among the most common strike characters are those used for copper coins. When copper coins are struck, they typically display distinctive red luster. Over time, this red luster fades and eventually turns to a rich brown patina. NGC
uses three primary strike characters after the numeric grade to describe the amount of red and brown present on the coin's surfaces: "RD" (for red), "RB" (for red brown) and "BN" (for brown).
A coin with a RD strike character must exhibit at least 85% of its original red luster. Read the Entire Article