Here is an 1901-O Barber Quarter in PCGS XF45.  After the 'Big 3' key dates (1896-S, 1901-S, 1913-S) in the Barber Quarter Series, there are a group of 5, including the 1901-O, that are less common than the rest of the series and very rare in CAC/CACG quality.  For the 1901-O, only 8 have been CACed in XF45.  For all of the AU grades, there are only 8 in CAC, and none in Grades 61-63.  So if one needs this date in CAC, it comes around just once in a while. 
 
This example is certainly worthy of the CAC sticker.  A nice patina with a hint of color near the edges, minimal hits, and a silky luster under the light.  Everything an original XF should be.  
 
This coin is approved by CAC.
 
PCGS Cert. #16133743