What is "Key", when Collecting Coins? (numismatic rare coins)

But, if the Collector is putting together the same set, in Gem BU Condition, the 1919-D and the 1921-S would be considered the “keys” and the 1916-S likely would not, because the 1916-S either not available at all, or is plentiful. Also Key Date may be a replaceable term.

Another example, using Lincoln Cents: The "key dates" for the Lincoln Pennies, from 1909 -1958 (wheat cents) are: 1909s, 1909s VDB, 1914 D, 1922, and the 1931 S.

by: Robert L Taylor, JD


-numismatic rare coins