Wrong actually, when Evelyn uses it to heal one of those chaps it also behaves as a Star Stone unlocking a homestead portal....that's pretty bloody big deal to miss. Blood stone, I don't care so much about except for other quest purposes like healing fools that can't be healed with good ol healing magic.
There are plenty of other stones, so it's not a big deal at all. You can find enough stones to unlock all portals and still have several to spare.
Actually, she has a bloodstone on her when you first talk to her. You can pick-pocket it away, and she will be unable to heal anybody.
I stand corrected. Thanks.
I seem to remember making her run without using it, and then finding it on her later, but that may have changed since I was testing in the beta.
I am doubting myself now. Perhaps she did have the stone with her, but I sure didn't find one. There's the chance I missed it though. Maybe it's still lying around in her lair. :S