fossil

Polished petrified wood

Silicified wood, primarily microcrystalline quartz (SiO₂) replacing organic tissue

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown, tan, cream, and gray wood-grain banding with a dull to vitreous polish. It is dense, non-cleaving, and commonly shows preserved cellular texture and specific gravity around 2.5–2.7.

Identified August 11, 2026More fossil →

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Physical properties

Formation & geological history

Groundwater rich in silica gradually replaced buried wood, often during volcanic or sedimentary burial; specimens range from Paleozoic to Cenozoic in age. The image shows a small cut and polished fragment.

Uses & applications

Used as an ornamental stone for cabochons, carvings, bookends, and jewelry, and collected for its fossilized wood pattern. It has modest commercial value unless the grain, color, locality, or size is exceptional.

Geological facts

Unlike ordinary wood, petrified wood is mineralized while retaining the original growth rings and cellular structure. Red or yellow colors commonly result from iron oxides, while darker tones may reflect manganese or carbon.

Field identification & locations

Identify it by visible wood grain, cellular patterns, glassy hardness, and inability to scratch with a steel knife; quartz-rich pieces may scratch glass. Common deposits occur in the western United States, Madagascar, Indonesia, Australia, and Argentina.