Gem Brilliant Uncirculated (Gem BU) is an adjectival coin grade that dealers and collectors may use to describe the condition or grade of a coin. This is different from the Sheldon Scale of Coin Grading that includes a relative numeric value to help further describe the grade of the coin. A coin's grade is one of the many factors that go into determining the value of a coin. The American Numismatic Association (ANA) has published The Official Grading Standards for United States Coins guidebook that can help you learn how to grade United States coins using official ANA coin grading definitions.
Gem Brilliant Uncirculated (Gem BU) is the coin grade assigned to a coin where the strike is sharp and the devices have no evidence of wear. The mint luster must be stunning. The coin's eye appeal must be above average and there are no bag marks and/or abrasions that are visible without magnification.
Alternate Spellings and Terminology
gem brilliant uncirculated (when used as a descriptor to designate the grade of a United States coin, this term is always capitalized).