fossil

Petrified wood (likely agatized or silicified wood)

Silicified wood; primarily microcrystalline quartz (SiO₂), often with chalcedony and iron oxides

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; mottled brown, reddish, gray, and cream colors with earthy to slightly waxy luster. Quartz replaces the original wood structure, commonly preserving grain, pores, or growth patterns; no obvious cleavage.

Identified August 15, 2026More fossil →

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At a glance

Common name: Petrified wood (likely agatized or silicified wood)
Scientific name: Silicified wood; primarily microcrystalline quartz (SiO₂), often with chalcedony and iron oxides
Category: fossil
Identified: August 15, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small ordinary rough piece; $30–$150+ for attractive, well-preserved or vividly colored specimens.

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

Formed when buried wood was gradually mineralized by silica-rich groundwater, commonly during volcanic or sedimentary burial. Ages range from tens of thousands to hundreds of millions of years, depending on locality.

Uses & applications

Used as a lapidary and display material, in cabochons, carvings, bookends, and polished slices; generally more valued for pattern and preservation than industrial use.

Geological facts

Iron oxides create red-brown coloration, while manganese or other impurities can produce darker tones. The pictured specimen appears heavily weathered and may also contain iron-rich breccia or agate.

Field identification & locations

Look for preserved cellular or wood-grain texture, unusually high density, and inability to scratch it with a steel knife. Common localities include Arizona, Indonesia, Madagascar, Australia, and Oregon; definitive identification may require a cut or polished surface.