Petrified wood is a name for special kinds of fossilized remains of certain types of vegetation.
It happens when trees or similar woody plants transition completely to stone through what is known as permineralization.
During the process, all of the organic material is replaced by minerals such as quartz or some other silicate.
At the same time, it retains the original structure of the stem tissue.
Unlike certain kinds of fossils that are usually compressions or impressions, petrified wood is an actual representation of the original organic matter in 3D.
In this article we will cover:
How is it Formed?
Petrified wood forms over time when organic remains are replaced by minerals through a very slow petrification process that ultimately ends in quartz chalcedony mineralization.
This process takes place underground after wood becomes buried beneath volcanic ash or sediment. It begins its preservation process because of a lack of oxygen, which prevents decomposition.
There are certain conditions that have to be met before the organic material can be changed into petrified or fossil wood.
Generally speaking, the organic matter becomes buried in an oxygen-free environment that preserves the original structure of the plant as well as its general appearance.
Other conditions that must be met include having regular access to water rich in minerals, which must make contact with the tissues.
This will replace the organic plant matter with inorganic minerals to create the petrified wood, wherein the material is turned to stone.
Exotic minerals can sometimes create the green and red hues that show up in rarer organisms.
Some of the minerals that are found in petrified wood include silicon dioxide, which is the base mineral for chalcedony, opal and quartz, calcite, iron oxides, manganese, cobalt, chromium, copper, and many others.
Why is Petrified Wood Heavy and Hard?
Petrified wood is approximately two or three times harder than average wood, depending on its type. The heaviness of the material is generally owed to its composition.
Beyond that, the heaviness of the material is also dictated by how densely packed the molecules are with the material in question.
With materials that are densely packed, meaning that the molecules are found close together, more molecules can be located in a sample as opposed to materials that aren’t as dense.
Regarding materials that make up living wood, the minerals in the petrified wood are denser than the molecules.
Therefore, the density of the molecules that determines whether or not wood floats is also what is responsible for the weightiness of petrified wood.
Is it harder than a piece of rock?
The answer to this question depends on several things. As mentioned, the heaviness of the material is dictated by the density of its composition.
Some rocks are lighter than others due to their composition, with pumice, for example, being quite lightweight. It floats and is not dense at all.
For this reason, petrified wood can be heavier than some kinds of rock, though it may be lighter than others. The sample sizes being compared also factor into the comparison.
Can Petrified Wood Get Wet or Is It Waterproof?
The simple answer to this question is that, yes, petrified or fossilized wood can get wet. This type of wood isn’t completely waterproof.
Still, for a number of reasons, it isn’t recommended that you soak this wood in water for any length of time.
The organic material found in petrified wood has been replaced completely with certain minerals.
When the petrified wood is placed in water, the materials won’t absorb the water like wood made from organic material might.
Because of this, placing petrified wood in water for short periods of time if you need to clean it likely won’t harm the wood; however, extended periods of time are not recommended as this can harm the material.
Think of it as petrified wood is a stone, because technically it is: if you put a stone in water, the molecules of water find their way into the cracks of the stone.
These water molecules can cause the slow widening of fissures over time, which can cause the stone to break or crack apart.
If you are hoping to make the wood into a sculpture, table, or another item of value, this can be detrimental to its durability.
Water Can Cause Rust or Discoloration
Petrified wood usually gets its hue from metals being present. Letting the wood sit in the water or otherwise get wet constantly can cause it to rust, which can turn the wood yellow and cannot be scrubbed clean.
If you let the wood get wet for long periods of time, the yellow can become an unsightly reddish-brown stain that is also difficult to remove.
When this occurs, sometimes you have to grind the rust off or cut it instead.
Also, remember that sometimes it can be difficult to know just what the petrified wood is made from. There could be toxic materials or metal in the stone that react poorly to the presence of water.
Some of the chemicals can leech into the water or even let off toxic gas into the air.
Keep in mind that just because a surface looks safe, it doesn’t mean there is nothing lurking beneath the surface that can interact with water.
Water Can Cause Damage to the Finish of Petrified Wood
The wood sitting in water can also harm the finishes added to petrified wood.
A lot of commercially sold minerals are coated with a thin layer of certain products that are made to give the stone a shinier, brighter look.
Such materials are sometimes oils, which you’ll have to reapply periodically. Other times, these commercial products have a tint to them to make the stone look better.
Regardless of the finish, when the finishes are stripped away, the stone will appear duller.
Water is also capable of diminishing the natural shine of a material, since the water molecules will sink into the surface of the stone, reducing light’s ability to refract the way it once did.
Soaking it in water can also facilitate other changes to the colors of the stone in a way that only grinding or cutting can remedy.
Collectors will often soak finished petrified wood in salt or mineral water thinking this would strengthen and clean it, only to be disappointed with the finished result.
Hi, I am Mark Garner a professional carpenter, woodworker, and DIY painter. I live in the small city of Peoria, Arizona as a semi-retired woodworker. I have started this blog with a simple motive to help you with my wood experience in this sector. If you like to know more about what I love doing and how it all got started, you can check more about me here.