fossil

Fossilized wood or plant fragment

Petrified wood (silicified fossil wood; commonly Araucarioxylon or related taxa)

AI-generated identification · may be incorrect

Dark brown to gray, layered grain-like texture with a dull to slightly waxy luster; silica commonly replaces cell walls while preserving wood structure. Hardness is typically 6.5–7 Mohs, with no obvious cleavage and specific gravity around 2.5–2.7.

Identified September 7, 2026More fossil →

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Physical properties

Formation & geological history

A woody fragment was rapidly buried and mineral-rich groundwater replaced or filled its tissues, usually with chalcedony or quartz. Petrified wood forms in sedimentary volcanic-ash environments over thousands to millions of years, often during the Mesozoic or Cenozoic.

Uses & applications

Used as a decorative stone, cabochon material, paperweight, and educational fossil specimen; larger pieces are used for polished slabs and furniture accents.

Geological facts

The visible parallel bands may represent preserved growth rings, bark, or wood grain. Silicification can preserve microscopic cellular detail despite complete mineral replacement.

Field identification & locations

Identify it by wood grain or cellular patterns, stone-like hardness, and lack of organic flexibility; a steel file should not easily scratch it. Common deposits occur in Arizona, Madagascar, Indonesia, Argentina, and Australia.