Peanut wood is a variety of petrified wood that is usually dark brown. It is recognized by its white-to-cream-color markings that are ovoid in shape and about the size of a peanut. It received its name from these peanut-size markings. The peanut wood began its life as a conifer tree on land in the area now known as Western Australia. When these trees died, rivers carried them into a sea. This was during the Cretaceous time period.