Saturday, October 26, 2013

Petrified Wood Explained

For today's post, I thought I would talk about another fossil. Last post was about fossilized dinosaur bones, this one will be about fossilized or petrified wood.

Petrified Agatized Indonesian Bird's Eye Palm Root

There are as many types of petrified wood as there are trees, just about. The variety is endless. Sometimes, it is used for jewelry, but it is also avidly collected as specimens. Petrified wood can be found as huge stone tree trunks or as small broken off pebbles. Large pieces are often used as display. The best pieces for jewelry contain very nice wood patterns or a rainbow of colors.

Agatized Petrified Wood

If a tree were to fall in the woods, it would rot in the atmosphere and be eaten by bugs and such. However, if a tree falls and is protected from oxygen and the elements by ash or mud before it rots, and is subjected to mineralized water, it begins the process of petrification. Petrification is a long process by which every part of the trunk (leaves and branches typically will rot before petrification can happen) is replaced by minerals in the water that slowly seeps through. Those minerals settle into the cells of the trunk and by the time the cells decompose all that is left is the mineral mold of the cell. The replacement mold can be opal, silica, calcite or pyrite to name a few. The result of time and petrification is a very detailed model in stone, or fossil, of the tree right down to the cell and rings.

Opalized Petrified Wood

Agatized Petrified Wood

Petrified wood goes by many names; fossilized wood, opalized wood, agatized wood, or silicified wood (opal or agate replacement). Petrified wood is deceptively heavy. One might see some on the ground and pick it up thinking it is a neat piece of wood only to find it to be a heavy rock. It looks very convincing! The color of the petrified wood would depend upon what replaced it and the minerals in the soil. Some are rainbow colored and some look just like wood. Because of it's beauty, it is used in jewelry, cut en cabochon. Petrified wood takes a very good polish and is very hard. The hardness is generally that of agate or 6.5 to 7 on the Mohs hardness scale. 

Arizona Rainbow Petrified Wood

Petrified Brazilian Fern Tree
 I love pet wood. I enjoy working it because it is hard and takes a great polish. I am always looking for slabs with interesting wood patterns or colors. I have plenty to cut, but I have finished a few which I am including here to show the variety. Pet wood is often known by the local in which it was found. The type of tree is not always known, but knowing, at least, a locality is nice. Washington State and Arizona are two popular places for pet wood, but certainly not the only places, as it is found in so many areas.

Another Indonesian Petrified Palm Root

Rare Hell's Canyon Petrified Wood

That's it for today's mini excursion into the world of petrified wood. I hope you learned something, I know I did when I put this together. :)

In case you were wondering.... the 2nd, third and last pictures were taken with pet wood props. :)


  1. In our wanderings on our motorcycles through the southwest, we passed areas, especially Arizona, with petrified wood. I never understood and find it amazing how nature does this through time with a combination of natural processes.

    1. Hi Kate, or should I call you wandering Kate? :) Have you ever picked up any pet wood? There is virtually nothing on the coast to pick up. :( I would be so excited to find and cut my own rough.

  2. Tela, I am in love with your petrified wood pendants. Wowza. That first one (palm's root) is absolutely stunning!! We are planning on a trip to the petrified forest in Arizona this February. Is there anything you want me to look out for you?

    Hopefully you continue to heal this holiday season and are able to continue to make so much beauty with your wrapping and your rocks.



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