You may also like. 11.49 3518g POLISHED PETRIFIED WOOD FOSSIL AGATE SLICE DISPLAY Madagascar A1243. Silicified wood is mainly generated in the Mesozoic period, most in the Jurassic and cretaceous. Petrified wood, is millions of years ago or earlier after trees are quickly buried underground, replaced by SiO2 (silica) in the groundwater of fossil trees. […]