This Specimen has been sold.
Large 13 inch Petrified Wood Slab - Madagascar
This is a large, richly colored petrified wood slab mined near Ambilobe, Madagascar. It is approximately 13x10.5 inches and one side has been polished to a mirror like finish. The polishing was done by one of the best polishers out there, and doesn't have scuff marks or dull spots like lower quality material. The color variety and detailed wood structure make this specimen second to none.
Petrified wood is the name given to wood that has been turned into stone (fossilized) through the process of permineralization. All of the organic matter becomes replaced by minerals, while much of the original structure such as tree rings in retained. For this to happen the wood needs to be buried in an environment both low in oxygen (preventing decomposition) and with flowing, mineral-laden water. The coloration is due to the various minerals that are present during fossilization. For example red colors are due to iron compounds, greens due to copper, etc.