The Mint defines "Uncirculated" (Mint Set) coins as being struck on lower-speed presses with greater striking force, they are also struck and packaged in their own separate areas off the main production floor.
In general numismatics, "uncirculated" is a condition grade, the U.S. Mint uses it to mean a manufacturing process (a la Proof).
One "anomaly" are those "S" BU Quarters. They look every bit as good as Uncirculated P-D Mint Set coins, even though the Mint makes no claim they are produced as Uncirculated. The "S" BU quarters may in fact be produced in the exact same manner as Uncirculated P-D Mint Set coins (or one slight difference, such as main floor production or a high-speed press being run a lower speed...)
Edited by DNA
11/07/2013 12:16 am