fossil

Petrified wood

Silicified wood, commonly quartz (SiO₂) replacing woody tissue

AI-generated identification · may be incorrect

Brown, reddish, and gray fibrous grain with a dull to slightly waxy luster; typically Mohs 6.5–7, specific gravity about 2.5–2.7, with quartz microcrystals preserving cellular wood structure. The specimen appears rough and weathered, but image-only identification is provisional.

Identified August 16, 2026More fossil →

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Physical properties

Formation & geological history

Mineral-rich groundwater gradually replaces buried wood, usually with chalcedony or quartz while retaining growth rings and texture. Petrification occurs in volcanic ash, fluvial, or sedimentary settings over millions of years; its precise age and locality cannot be determined from the image.

Uses & applications

Used as a lapidary material for cabochons, carvings, bookends, and polished slabs, and collected as a fossil. It has little industrial value in small rough pieces.

Geological facts

Unlike ordinary wood, petrified wood does not burn and can preserve microscopic cellular detail. Color commonly comes from iron oxides, manganese, carbon, or other trace impurities.

Field identification & locations

Identify it by visible wood grain, very high hardness, silica-like fracture, and inability to scratch with a steel knife; a streak or hardness test can help distinguish it from ordinary fossil wood. Common localities include Arizona, Indonesia, Madagascar, Brazil, and Australia.