Unpolished Petrified Wood Limb - Blue Forest

This is a rough (unpolished) limb section of petrified wood from the famous "Blue Forest" in Eden Valley, Wyoming. It was formed when trees died and fell into a swamp where they are rapidly covered by algae. This formed casts that preserved the original bark surfaces of the trees and kept them from decaying. Eventually the algae casts and the spaces between them were filled in by minerals, often in exquisite, crystalline form.