7.1" Polished Petrified Wood Log - Arizona
This is a 7.1" wide section of a petrified log which has been cut and polished on one end. The polished face shows some excellent patterning while the exterior of the log has some great detail too. It's from the Chinle Formation of Arizona, renowned for it's beautiful rainbow wood, but getting pieces like this are a little more unusual.
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.