Castiel being Castiel, there's no rush in him to disturb the person with the glowing blue stone. When one lives forever, patience is something he has in spades. Humans with tails is a new thing, after all. Things such as Jedi don't exist in his world, although he's heard Dean and Sam make more than a few jokes about the movie that he didn't get at all. At least there won't be any spoilers from his end.

"Why does it glow?"

The question isn't whispered or shouted, only spoke with real curiosity. In his mind, she must be a witch since they're the only ones he knows for a use of lit-up rocks. Or that could make them light up.