Is this really wood? Well, it certainly used to be! Petrified wood is a fossil formed when minerals impose themselves upon cavities between and within the cells of natural wood. This process is usually undertaken by silica or calcite, and the replacement of the organic tissue with the minerals can be so precise that the internal structure, as well as the external shape, can still be very well-represented. The result is that the wood takes on a calcified appearance, while still retaining the basic characteristics of the wood, and different minerals can give petrified wood a range of diverse colorations, making each specimen totally and markedly unique. A beautiful example of incredible geological forces, this will be an excellent addition to a comprehensive rock collection in the science classroom, or for the rock collector in your family.
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