How Does Wood Become Petrified

How Does Wood Become Petrified?


How did the Petrified Forest form?

Can petrified wood be used to make furniture or as building material for homes?

Petrified wood is actually a fossil and just like dinosaur fossils, these were made by the natural action of sedimentation and petrification. It can take a long, long time to make petrified wood, therefore, it will just be a waste to use it as furniture or as a building material.

How wood becomes petrified

Petrified wood forms when plant material is buried by sediment. Sediment like dirt, ash and small rocks completely bury wood and protects it from decay from the action of oxygen and organisms. As sediment moves inside felled wood, groundwater moves in as well. This water is rich in dissolved solids and this replaces the original plant material with silica, pyrite, calcite and other material.

The result of these processes is a fossil of the original tree but with preserved details of the bark, wood, and cellular structures of the tree.

How long does wood become petrified?

Petrified wood is from fallen trees that usually get washed down in a river or has fallen into a lake. This wood becomes buried under layers of mud as well as ash from volcanoes and other types of materials.

Sealed under these rotting layers is material that has been deprived with oxygen which is the necessary ingredient for decay. As the organic tissues break down over time, the resulting open sections are filled with minerals like silica.

Over millions of years, the minerals that settle inside the crevices of wood crystallize to form a stone-like material known as petrified wood. It is not right to call wood “wood” anymore because it has now become like the minerals that have infiltrated the wooden material.

Petrification can take millions of years, or not?

Petrified wood can take millions of years to form. The natural action of sedimentation and the penetration of minerals is a slow but efficient process that cannot be rushed. The result is like mineralized wood which is as strong as a rock.

But do you know that there are studies that show that wood can actually petrify quickly? Not as quick as a year but definitely less time than it takes for wood to decay and petrify in a natural environment.

Two ways to petrify wood

Wood can be petrified in two ways both of which usually involve being buried in volcanic ash. This material decomposes due to exposure to water and nourishes wood with groundwater enriched with silica.

In the first process, wood is found in a hot silica-rich environment; a good environment to petrify wood. Each molecule of wood decomposes and is carried by water. After this, it is replaced by a molecule of silica.

When the replacement of the molecules is complete, the mineral impurities in the silica become responsible for different beautiful hues on wood. This kind of petrified wood can be polished and displayed to create an object of amazing beauty.

Once the process of silicification (silica enters the voids in the wood) is complete, organic material will be removed completely. The hints of the tree rings may be preserved if the minerals change over time. Most of the petrified trees found in the Petrified Forest of Arizona were petrified using this kind.

The second type of petrification uses the complete infiltration of the wood by silica-rich water. The silica or calcite, or a combination of both, can infiltrate the pores of the wood and this prevents the complete decay of wood.

This process lets individual cells to be well preserved but no doubt that the tree ring pattern can still be seen easily, and appreciated. The petrified trees in Yellowstone Park were made using this process. The process is quicker and the petrified trees show the same results with the lovely rings still visible.


Petrified wood is made by years, millions of years, of natural decomposition and silicification. Wood that has been petrified becomes the actual mineral that has infiltrated it. This makes wood stronger and very resilient to rot. Wood also loses its lovely wooden color.

It will become the actual color of the material that has filled its void. Truly a remarkable sight, therefore, you might want to reconsider using petrified wood for furniture and as a building material.

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