The 21st Ring of Power?

I don't think "Saruman of Many Colours" came from his robe. I think he adopted the "Many Colours" motif to indicate his plans for universal domination or his assumption of the powers not granted to Istari (who only had four colors), and the robe was merely an affectation indicating this.

If Saruman's ring were a power object, I think the good guys would've shown more concern about it. As far as we know, no one tried to take the ring from him, so it wasn't terribly important. (Or Gandalf forgot to tell Treebeard, "Don't let Saruman go without divesting him of his ring!")

I'm kind of shocked that so many people missed the fact that Saruman made a ring. I've only read the book once, and that was one of the stand-out moments. "He wore a ring on his finger," was the perfect line to establish what was about to happen. Saruman obviously didn't normally wear rings, or else Gandalf wouldn't have mentioned the ring -- what does this outward change foreshadow?