3.15" Stromatolite Covered Petrified Yew (Taxus) Slab - Nevada

Petrified wood is the name given to wood that has been turned into stone (fossilized) through the process of permineralization. In this process, all of the organic matter becomes replaced by minerals, while much of the original structure, such as tree rings, is retained. For this to happen, the wood needs to be buried in an environment low in oxygen to prevent decomposition and with flowing, mineral-laden water, so minerals may replace structures. The coloration is caused by various minerals that present in that water during fossilization. For example, red colors are due to iron compounds, greens due to copper, and so on.

Stromatolites are the layered trace fossils of microbial life, primarily cyanobacteria. Some of them date back an astounding 3.4 billion years, making them the oldest record of life on Earth! Stromatolites and Microbialites were typically formed in shallow water by the growth of layer upon layer of cyanobacteria, a single-celled, photosynthesizing microbe. These layers often form very beautiful and colorful banded structures in the rock.

These oxygen-producing cyanobacteria were so simple they lacked a DNA-packaging nucleus, but were responsible for possibly the largest changes the earth has undergone. They were the only major source of atmospheric oxygen critical for the development of more complex life.