Is there a way to mount a crystal ball on a stair post finial?
i've actually done this myself and love the way it looks.  can't tell you how many compliments i receive on it.
but i think the compliments are because i took it a step further and ran some battery powered lights to them, so they double as night lights.
i just glued them in place with an epoxy and they've been holding for 9 years and counting.
i've included a photo of the ball and also tried to cover it up with a blanket to take one in the dark with the light on.
the house is over 100 years old, so i don't mind it not being perfect. if anything, the glue looks like a bit of dust in there.
i just noticed that the first photo also shows the one at the bottom of the stairs...

 :)