fossil

Polished fossilized wood (petrified wood), likely agatized

Silicified wood; predominantly microcrystalline quartz/chalcedony (SiO₂), with iron-oxide coloration

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown, reddish, golden, and black banding with visible wood grain and cell structure. Usually dull to waxy or glassy when polished; fine-grained cryptocrystalline quartz replaces the original organic material, with possible pyrite or iron-oxide inclusions.

Identified September 4, 2026More fossil →

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At a glance

Common name: Polished fossilized wood (petrified wood), likely agatized
Scientific name: Silicified wood; predominantly microcrystalline quartz/chalcedony (SiO₂), with iron-oxide coloration
Category: fossil
Identified: September 4, 2026
Method: Standard

AI Estimated Value

Approximately $30–$150 for a common polished specimen; $200–$1,000+ for large, vividly colored, well-preserved, or rare agatized 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

Silica-rich groundwater gradually replaced wood tissue and filled pores during burial, commonly in volcanic ash or sedimentary deposits. Fossilization may range from tens of millions to over 200 million years old, depending on locality.

Uses & applications

Used as decorative slabs, bookends, carvings, cabochons, and collector specimens; unsuitable for ordinary construction because of rarity and aesthetic value.

Geological facts

The concentric growth rings and radial cracks mimic living wood, but the material is stone. Golden metallic-looking patches may be pyrite, chalcopyrite, or iron oxides; exact identification requires testing.

Field identification & locations

Identify by preserved grain, stone-like weight, lack of organic fibers, and quartz hardness; it should scratch glass but not be scratched by a steel knife. Common sources include Arizona, Indonesia, Madagascar, Australia, and the western United States.