Authentic petrified wood is hand-cut and polished into bookends. Each stone is unique and will vary in size, pattern, and color. Some cracking is natural. Because this is a product of nature and not controlled, all pieces will vary in size, shape, color. There are no two alike. A natural product, each piece of petrified wood will be somewhat unique in size, shape and color based on minerals in soil and, therefore, each will have it's own unique character. Variance should be expected and range from natural, brown and black--nature's work of art. Other natural traits are knot holes and cracking. If rested flat, coasters are advised to prevent staining. For more detailed information on the nature of your petrified wood product, please click "Details".