Third Eye Moving Crystal?

QUESTION: When I meditate sometimes I like to place crystals on my third eye, idk if that’s weird lol it just helps me get deeper into my meditation. Anyways the last couple times I’ve noticed I feel the crystal moving back and forth. For example: the first time it happen I use a long selenite crystal. It’s pretty long so I sat it on my third eye horizontally. Once I got comfortable in meditation and it had been there a while I felt it balancing from side to side, the deeper into meditation I got the more clearly I felt it.

What’s happening? I’m not scared just curious since I can’t see if it’s actually moving or not. Either way it’s pretty cool ☺️