Answer:
In marble halls as white as milk, lined with a skin as soft as silk. Within a fountain crystal-clear. A golden apple doth appear. No doors there are to this stronghold, yet thieves break in and steal the gold.
You can always see it, but it's too far away to touch. Mountains rest on it, and at sea it surrounds you. What is it?
What does everyone know how to open but not how to close?
What looks back but cannot see?
Blend a teapot shot so the pearlies wonβt rot!
Bury deep, Pile on stones, My mind will always Dig up them bones