Large 8 inch Tall Agatetized Polished Petrified Wood Bookends. The base of each bookend measures 6″ Long x 3″ Wide and 3/4 High. Each bookend is 7.75″ to 8″ Tall x 5 Wide. Each Bookend weighs in at 4 Lbs 12 oz equaling a combined weight of 9 Lbs, 10 oz. The facing side of each bookend has a polished finish. 200 Million Years Old. Petrified wood (from the Greek root petro meaning “rock” or “stone”; literally “wood turned into stone”) is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization. All the organic materials have been replaced with minerals (mostly a silicate, such as quartz), while retaining the original structure of the stem tissue. Unlike other types of fossils which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material.