The difference between Wood Replacement and Petrified Wood is the entire wood cell structure has been replaced with agate after the wood has decayed and left a chamber for the agate to settle in. Petrified wood is the actual transformation of the wood into agate through the process of absorption of the minerals into the cells of the wood.
By far the most famous area for Petrified Wood is the Petrified Forest in Arizona. Long closed to rock hounds to preserve the enormity of the forest and protect for generations to come. This area is part of the Chinle Formation, approximately 180,000,000 years old. Petrified wood is found throughout the world, where ever volcanic eruptions occurred. The petrification process is rather complicated to explain in a brief description; however, it is the result of pressure, lack of oxygen and the infusion of minerals which produces an agate much harder than steel. Petrified wood can contain pyrites, marcasite, or calcite but the most common is agate, jasper, or opalized wood. The wide array of colors is due the mineral content of the silicified water and the time involved in completing the process. Below is a list of the minerals and their respective color hue:
- Copper – green/blue
- Cobalt – green/blue
- Chromium – green/blue
- Manganese – pink
- Carbon – black
- Iron Oxides – red, brown, yellow
- Manganese Oxides – black , blue, and purple
- Silica – white, gray
Some of the more noted types of petrified wood in the United States are:
Arizona Rainbow Wood
Blue Forest Wood
Chrome Green Wood
Hampton Butte Green Wood
Moh’s Hardness 7.5 – 8
Shown below are two types of Petrified Wood as well as two types of wood replacement: Arizona Petrified Wood and Blue Forrest Petrified Wood; Texas Springs Wood Replacement and Live Oaks County, Texas Wood Replacement. The last type is sometimes referred to as Plume Wood.
Live Oaks County Texas
Both Petrified and Wood Replacement are getting scarcer each day as new laws are passed and private lands become less accessible. Whatever is in private collections or stashed away by old school lapidaristâ€™s is most likely what will only be available in the years to come.