$20 Saint-Gaudens Gold Coins XF
"XF" is a contraction for the denotation of "Extremely Fine". On the Sheldon Scale, Developed in 1949 by Dr. William Herbert Sheldon, which ranges from 1 on the low end to 70 on the high end, XF coins tend to fall in the 35-45 range. A Saint-Gaudens gold coin in this grade has been circulated, although due to the rather high purchasing power of $20 when these coins minted and used as currency, they probably did not see use often, and a $20 gold piece would not be considered pocket money. These coins more closely track the spot price of gold, and are not considered "Bullion" coins and offer benefits bullion coins do not.
Specifics of the Grade
A $20 Saint-Gaudens may receive a grade of Extremely Fine for a myriad of factors, which may include "Bag marks" which occur when the soft gold coins in the bottom of a sack of coins are marred by the weight and movement of other coins in the sack rubbing against them (Think a sack of gold coins being transported by stage coach). Also, an XF coin may have been struck by a worn die, showing cracks and less than optimal intricate detailing of the coin's design. Also in the XF designation, any nicks or scratches probably occur on the most prominent design of the "Striding Lady Liberty" on the front of the coin, or the nested eagle design on the reverse of the coin, as opposed to the "Field" or blank areas of the coin's design.