Originally Posted by Dazrin
I thought it was explained somewhere in there that the rings changed color due to some accident or getting blood on them. It has been a while though since I have read them so it could certainly be a different book that I am remembering.
It could be that that is the mythos that has grown up around the rings in question as far as those characters who come in contact with them are concerned. Such things tend to overlook the often mundane reality of the true reason I think. For example there is supposed to have been a real Nicholas Flamel who was fairly well off in terms of having money as he founded several hospitals and such. Of course people back then claimed he must have the philosopher's stone in order to have such wealth. The reality more likely is he probably was just a shrewd business man who knew how to handle money.