Petrified wood is a unique type of fossil that preserves the impressions of the organic material down to a cellular level.

The most common plant fossils are often only impressions of anatomical details left upon soft earth during fossilization. Petrified wood, however, is a substance wherein minerals fill and replace cavities left by buried plant material, allowing for an in-depth and three-dimensional look at the original plant.

This specimen is a highly polished, cross-cut segment of petrified wood. This particular specimen comes from Arizona. A small information card is enclosed with the material, which also serves as the certificate of authenticity.

Please Note: Like the branches of any tree, the size, color, and patterns of this specimen vary widely. This specimen has been photographed individually to show the unique shape and pattern of the material. You can see more petrified wood in the collection below.

The process begins when wood is buried underneath sediment or volcanic ash. Under these conditions, the structure of the plant can be kept safe from decomposing organisms due to a lack of oxygen. At this point, there are two mechanisms by which petrification occurs: permineralization and replacement. Permineralization is the filling of cavities within the plant, ranging from the insides of cells and tissues to non-native spaces such as gaps created by rot or insects. Replacement follows after the degradation of cellular walls and describes the process through which sediment fills the gaps left behind. Both these mechanisms require minerals to be transported through the plant system, often time by sediment-laden groundwater.

Petrified wood is found in a wide range of colors, from cool blues and greens to warm reds and pinks. Silicates like quartz are the predominant mineral in petrified wood which, in a pure form, is colorless. Crystal defects caused by inclusions of other elements can change the color of the mineral, making these trace elements responsible for the array of sunset colors that appear within petrified wood.

Iron is the most influential element in determining color, as the inclusion of the element can manifest as a whole rainbow of options. Even within the same fossil, changes in colors are directly connected to a change in the amount of iron present at a certain spot. As fossilization occurs over a very long timespan, stops and starts in petrification occur causing different colors to appear in different areas. This is what gives petrified wood its distinct and beautiful appearance.

Petrified wood can be found all over the world. The Petrified Forest National Park in Arizona contains an enormous deposit of petrified wood in the Chinle Formation. This formation was exposed through wind and water erosion. Other major deposits have been found in Brazil, Indonesia, and the coast of Madagascar.