How To Petrify Wood

How to Petrify Wood


Petrified wood is the result of years and years of natural preservation of wood. Petrification happens when trees, plants, and remains of animals are naturally buried by ash, soil, and silt. Water from the river or a lake delivers minerals to the wood.

In time, the insides of wood are not wood anymore. This becomes the mineral that the wood was infused in. This process has created trees found in the Petrified Forest in Arizona, USA.

Petrification of wood basics

The petrification process is a natural process that can take years to happen. Petrified wood is from plant material which has been buried by sediment.

Dirt, ash and small rocks will bury wood and protect it from decay (burying will protect wood from the natural action of oxygen and organisms that decompose organic material).

Naturally, sediment will move inside felled wood and groundwater will also penetrate wood as well. Groundwater is rich in dissolved solids and this replaces the original material found in the plant. Solids like silica, pyrite, calcite and other material penetrate wood and change its internal makeup and structure.

After years of being exposed to these elements, wood becomes fossilized of the original tree. The bark, the grain and the cellular structure of wood will be completely preserved and petrified.

How long does wood become petrified?

Petrification can happen for millions of years. The most popular petrified wood forest is the Petrified Forest in Arizona, USA. This forest is from fallen trees that become washed down in a river or have fallen into a lake. Wood becomes buried under layers of mud from the ash from volcanoes and other materials.

Under the layers of material, there is wood that is deprived of oxygen, the necessary ingredient for decay. The wood’s tissues start to break down over time; the resulting open sections become filled with minerals like silica.

It can take millions of years for petrified wood to form and this is mostly due to the minerals that settle inside the crevices of wood. These crystallize to create a stone-like material which now known as petrified wood.

The natural action of sedimentation and penetration of minerals is slow but this is an efficient process that cannot be rushed. Wood (some say that it’s not correct to call wood “wood” at this point anymore) becomes mineralized wood which is as strong as a rock.

Things used to petrify wood

  • Wood in log or board form
  • Silica-rich groundwater
  • Mud and ash

Ways to petrify wood

The first method to petrify wood is the most basic one that can take millions of years. The other method is simpler, faster but is not ideally the most recognized petrification process. Both techniques use volcanic ash which is crucial in the petrification process since volcanic ash contains silica as it decomposes and this effectively preserves and petrifies wood.

Natural petrification/silification (taking millions of years)

Natural Petrification Silification


In the first process, wood grows in a hot, silica-rich environment that is conducive for wood petrification. The molecules found in wood decompose and this is carried away by ground water.

Replacing these natural components are silica and other minerals that are very heavy and will settle deep into the wood. The silica deposits, as well as other minerals, are responsible for the different colors in the wood. After millions of years, the result is wood that can be polished, worthy as a display.

The first process is also known as silification which defines the natural process when silica enters the many voids in wood. As silification happens, organic material will be removed completely from the wood. Most of the petrified trees in the Petrified Forest of Arizona were created using this process.

Infiltration of silica-rich water (takes only years to happen)

Infiltration Of Silica Rich Water


The second technique is faster and experts say that the results are comparable to the natural petrification process. This uses complete infiltration of the wood by silica-rich water.

The silica or calcite, or a combination of both will infiltrate the pores of the wood and this stops the complete decomposition of wood. In this second technique, individual cells will also be well preserved while the tree ring patterns may still be seen. The petrified trees in Yellowstone Park were made using this process.


Petrified wood is made by millions of years, of natural decomposition of wood and a process known as silification. Silica-rich groundwater moves into the many voids in wood to preserve and petrify it. And after many years of silification, wood emerges petrified, colored and stronger.

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