The first main difference I noticed was color, the Charnon stone being reddish pink. It seems like this was the only stone with that color. Then there is Luger's stone which to my recolection was green, which had infected the Charnon stone with its "green-ness", which indicates that green may be a sort of corruptiony evil color until we come across Vigo Light, which is somewhat confusing. Then there is the generic standard-issue blue, occuring with all of the stonekeepers that seem to adhere to law, and don't question/are part of the social structure, as well as Vigo's stone sometimes (it seems like Vigo's stone only becomes green after he leavs the guardian council). Finally there is the Elf King's stone which is a pale white, an obvious allusion to the Irkling.
Then there are the designs carved into the stones, which I love to draw. the Charnon stone has that swirly design, which seems to be very common. Then there is Vigo Light's eagle crest -ish design which to my knowlidge is uniqe. After that are the various combinations of swirls and dots on the elvish stones, and finally the design on the Elf King's stone which is also an obvious allusion to the Irkling and/or the mask thereof. Lastly there are the standard-issue blue and uncarved stones which seem like they might have been mass-produced for the war.
So what do you think? Mabie the designes are a special privaledge, or mabie the color of your stone changes bassed on your personality?