Ranking Druids a la Karate Belts and Tolkien Wizards

I've decided to add a little extra something for druids in my world.

The standard name level advancement applies, but I thought it would be interesting to assign rankings like those you find in a Karate class according to the color of the belt of the person.  Black belt, white belt, blue belt and so on.

Also,  I thought, why not tie in some Tolkienesque into the mix at the same time and make the top levels match those of the Wizards in the books.  so Blue, Brown, Grey and White are the top most ranks among them.

As Druids ascend level groups, they are identified by a corresponding color:

• level 1-2; Green. Thus Frederick the first level druid is known to other druids as "Frederick the Green" 
• level 3-5; Orange 
• level 6-8; Red 
• level 9-10; Black
• level 11; Blue
• level 12; Brown
• level 13; Grey
• level 14; White 

 No, it isn't necessary and it doesn't really change anything about progression, but it seems fun to us so I did it.

Of course, the "mark" or signature of each druid a symbol for their name, in the color of their rank.In our case, again in a bit of honor to Tolkien, each druid's "mark" is the foot/paw/hand print of some creature.  Also, it could be a specific type of tree leaf or anything recognizable that the druid can draw or imprint on clothing, armor, or whatever it is they choose to leave their mark on.  

Each Druid, at character creation, chooses their "mark" and it is recorded so that no other druid can use that.  The human hand is yet up for grabs.  There is no Saruman or Gandalf the White in most of these games and in our Middle Earth campaign, those two have long been absent.