Specimen at a glance
| Mineral | Petrified wood (silicified) |
|---|---|
| Chemistry | SiO2 (quartz and chalcedony) |
| Mohs hardness | 6.5–7 |
| Crystal system | Microcrystalline quartz |
| Form | Polished / tumbled |
| You receive | The exact specimen pictured |
About this specimen
Petrified wood forms through a process called permineralization: wood buried in sediment or volcanic ash, cut off from oxygen, gradually has its original organic tissue replaced cell by cell with dissolved silica carried in by groundwater. Over millions of years, that silica crystallizes into quartz or chalcedony, preserving the wood’s original cellular structure — growth rings, grain, even bark texture — in stone form. The result is technically a mineral (mostly silicon dioxide) rather than wood, at Mohs hardness roughly 6.5–7, but it retains the visual record of the tree it once was.
This cross-section shows clearly visible growth rings on its polished dark face, with the natural, unpolished bark-textured edge left intact for contrast — a nice way to see both the finished and raw sides of the same process. Approximately 4 x 3.5″, it’s a substantial piece that displays well upright or flat.
A great conversation piece for fossil and mineral enthusiasts alike, and a tangible way to hold millions of years of natural history.
Inside Petrified Wood
Same tree, same growth rings — just replaced, atom by atom, with stone.
The story: Before a buried log can fully decay, silica-rich groundwater soaks through its cell structure and slowly deposits quartz and chalcedony in place of the original wood, molecule by molecule. The mineral takes over so precisely that growth rings, bark texture, and sometimes even insect damage survive perfectly preserved in solid stone.
Why collectors chase it: It’s a genuine fossil you can hold and handle like any other mineral specimen — wood grain rendered permanent, sometimes in vivid mineral-stained color.
Care: Durable like the quartz it’s made of; safe for regular display and handling, soft dry cloth to clean.
Petrified wood: the science
- Petrified wood is a pseudomorph: stone in the exact shape of the wood it replaced, sometimes down to individual cells.
- Iron and manganese in the groundwater add the reds, yellows, and blacks.
- Petrifaction needs fast burial with little oxygen, such as under volcanic ash or river sediment, so the wood mineralizes before it rots.
Go deeper
Want the full story on petrified wood: how it forms, how to identify it, and what makes a great specimen?
Read Petrified Wood: The Complete Guide Shop all Petrified Wood
Questions about this piece
What is petrified wood?
Petrified wood is a fossil. Buried wood was infiltrated by silica-rich groundwater, and quartz slowly replaced the organic material, often preserving growth rings and cell structure.
How hard is it, and how should I care for it?
It rates 6.5–7 on the Mohs scale. Very durable at around Mohs 7. Dust or rinse and air dry. Polished faces can be wiped with a soft cloth.
Is this the exact piece I will receive?
Yes. This listing was photographed individually, and you receive the exact piece shown in the photos.
