Remember that coin grading is the expression of an opinion that describes the condition of an individual coin that most dealers and collectors would agree with. However, there is room for interpretation of these standards between coin dealers and coin collectors. Grades of “mint state” or “uncirculated” also take into account the fact that the coin may not be fully struck. Coins produced in the Denver and San Francisco mints from about 1917 to about 1928 are usually lacking in detail because they were not fully struck at the mint. To determine if your Indian Head nickel is uncirculated, look at the highest points of the design as indicated using the color red on the photo. If the mint luster is worn away from these points, the coin cannot be classified as uncirculated. However, remember a weakly struck coin will exhibit flat spots in these areas. This does not preclude it from being uncirculated if it has full mint luster everywhere else.
The Official American Numismatic Association Grading Standards of United States Coins by Kenneth BressettPhotograde: A Photographic Grading Encyclopedia for United States Coins by James F. RuddyMaking the Grade: A Grading Guide to the Top 50 Most Widely Collected U.S. Coins by Beth DeisherGrading Coins by Photographs by Q. David BowersThe Official Guide to Coin Grading and Counterfeit Detection by John Dannreuther