At the end of IWD when you defeat Balhifet, it says that the crystal shard Crenshinibon is destroyed and so is all its power. Well the game is set before the time of Drizzt Do'Urden and so if it is destroyed how can there be a book starring drizzt about it if drizzt arives after it is destroyed!!

Hello,
I hate admitting that I know the answer to this, but...

if you read the second Dark Elf trilogy (story with the showdown with Ertu), it is stated that the C-crystal can make copies of itself. Regis at faced a copy when he first encountered it. That is why he was, deflated, when he meet-up with the real/original artifact in the second trilogy.

- Twilight