Answer:
This is needed both for courage and hardcover books.
A circle of stones, never in rows. Stacked one on the other, mystery it sows. What is it?
What hangs others yet can unintentionally hang itself?
Round as a button, deep as a well. If you want me to talk, you must first pull my tail.
Scythe of darkness, Shadow’s light. Guiding eye of thirteenth sight.
I’m grown from darkness but shine with a pale light. Very round I am and always a lady's delight.