fossil

Petrified wood

Silicified wood (commonly quartz/chalcedony replacing wood)

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; gray to black, with rusty iron-oxide patches and preserved growth-ring/bark textures. Typically vitreous to dull luster, microcrystalline quartz structure, and no obvious cleavage.

Identified August 25, 2026More fossil →

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Physical properties

Formation & geological history

A fossilized tree in which groundwater-derived silica replaced organic tissues while preserving cellular and growth-ring detail; commonly formed in volcanic ash or sediment during the Mesozoic–Cenozoic, though age varies widely.

Uses & applications

Used as decorative stone, polished slabs, cabochons, tabletops, and collector specimens; lapidary value increases with vivid colors and sharply preserved texture.

Geological facts

The wood texture is a fossil record, not merely a surface pattern; colors may reflect iron, manganese, or carbon impurities. Silicified wood can preserve microscopic cell structures.

Field identification & locations

Identify it by continuous grain or growth rings, bark-like cracks, stone-like weight, and quartz hardness; it should not flex or show fresh wood fibers. Common localities include Arizona, Washington, Indonesia, Madagascar, and Argentina.