Riddle

Odie sat at his computer deep in thought. His recent brush with a sphinx had given him the idea to write a riddle. He hoped to be able to come up with something as challenging as the riddle the sphinx had asked him.

After much consideration, this was the result:

More precious than silver, gold or fine gems.
It's something that lives in the heart of true friends.
It starts when we're born, but it won't end with death.
It's something we treasure beyond our final breath.

Now, all he had to do was challenge his friends to solve it.