fossil

Petrified wood (polished/cut slab)

Silicified fossil wood, commonly quartz/chalcedony (SiO₂) replacing wood tissue

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; tan, cream, and brown layered grain with dull to waxy luster. It preserves wood-like growth bands and fibrous texture; quartz is microcrystalline and lacks obvious cleavage, with specific gravity around 2.6.

Identified September 7, 2026More fossil →

Explore Petrified wood (polished/cut slab) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Petrified wood (polished/cut slab)
Scientific name: Silicified fossil wood, commonly quartz/chalcedony (SiO₂) replacing wood tissue
Category: fossil
Identified: September 7, 2026
Method: Standard

AI Estimated Value

Approximately $20–$100 for a common hand specimen or slab; $100–$500+ for large, highly patterned, well-polished, or locality-documented pieces.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Buried wood was gradually replaced by silica-bearing groundwater during diagenesis, commonly in volcanic ash or floodplain sediments. Specimens range from Paleozoic to Cenozoic in age, often tens of millions of years old.

Uses & applications

Used for decorative slabs, carvings, bookends, cabochons, and lapidary objects; mainly valued as a fossil and ornamental material rather than construction stone.

Geological facts

The cellular wood structure can remain preserved in microscopic detail while organic material is replaced molecule-by-molecule by silica and sometimes iron oxides.

Field identification & locations

Identify it by visible wood grain, growth rings, bark or cellular patterns, high hardness, and lack of fresh organic smell or softness. Common sources include Arizona, Utah, Oregon, Indonesia, Madagascar, and Australia.