Harry Potter and the Half-Blood Prince

[Khamûl]

King of the Istari, I believe I can see your point. Harry sees the ring when he and Dumbledore meet Slughorn for the first time. He also sees it at another point in Dumbledore's office (I can't put my finger on it at the moment). Later, this is what Dumbledore says:

"You are forgetting... you have already destroyed one [Horcrux] of them. And I have destroyed another."
"You have?" said Harry eagerly.
"Yes indeed," said Dumbledore, and he raised his blackened, burned-looking hand. "The ring, Harry. Marvolo's ring. And a terrible curse there was upon it too. Had it not been -- forgive me the lack of seemly modesty -- for my own prodigious skill, and for Professor Snape's timely action when I returned to Hogwarts, desperately injured, I might not have lived to tell the tale. However, a withered hand does not seem an unreasonable exchange for a seventh of Voldemort's soul. The ring is no longer a Horcrux."

I interpreted this as Dumbledore's hand was withered when he went and took the ring from Marvolo's house because it was concealed and protected by many powerful spells. Then once he had it, it wasn't a problem destroying the Horcrux. (We see later in the cave that it is quite an ordeal to even put your hands on a Horcrux that Voldemort has protected.) However, it does seem to be open to other interpretations, such as his hand was withered destroying the Horcrux, but the ring was still around afterwards, so it is possible to remove the soul without annihilating the vessel. I'm not sure if I agree with that, but I suppose it is a possibility.