Someone posted this link the other day...HBP is the Best HP Novel and they raise some interesting questions. Just a warning, it's really, really, really long.
I agree. When Marvolo Gaunt is wearing it, it's not cracked. When DD has it, it's cracked.
Maybe this is to show us that a horcrux vessel can remain fairly intact when the soul piece is removed? (Ala Harry??) Just a thought...
Thanks for the link. If I'm not on FR, I'm on Hogwarts Professor or HP Lexicon. total loser!! :)