fossil

Petrified wood

Silicified fossil wood; commonly composed of microcrystalline quartz (SiO₂) replacing the original wood

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown to reddish with wood-grain texture and a dull to waxy luster. The original cellular structure is preserved, while the silica is typically microcrystalline.

Identified October 12, 2026More fossil →

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Physical properties

Hardness about 6.5–7 Mohs; brown to reddish with wood-grain texture and a dull to waxy luster. The original cellular structure is preserved, while the silica is typically microcrystalline.

Formation & geological history

Forms when buried wood is gradually replaced or filled by silica-rich groundwater during fossilization; specimens range from geologically recent to hundreds of millions of years old.

Uses & applications

Used for lapidary carving, jewelry, décor, and collecting; large deposits are sometimes quarried as ornamental stone.

Geological facts

Petrified wood is a fossil, not merely wood coated with mineral; colors reflect trace elements such as iron and manganese.

Field identification & locations

Identify by preserved bark, grain, growth rings, or cellular patterns combined with stone-like hardness. Found worldwide, including Arizona, Indonesia, Madagascar, and Argentina.