Answer:
This is needed both for courage and hardcover books.
I am seen in the water. If seen in the sky, I am in the rainbow, a jay's feather, and lapis lazuli.
He has one and a person has two. A citizen has three. And a human being has four. A personality has five. And an inhabitant of earth has six.
I am cracked by Indiana Jones. What am I?
I can run but not walk. Wherever I go, thought follows close behind.
What is so fragile that saying its name breaks it?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?