fossil

Petrified Wood

Silicified Wood (primarily SiO2)

Hardness: 6.5-7 (Mohs scale); Color: reddish-brown, tan, and grey; Luster: vitreous to waxy; Texture: preserves woody grain and cell structure; Cleavage: none (conchoidal fracture).

Hardness: 6
Color: reddish-brown, tan, and grey
Luster: vitreous to waxy

Identified July 19, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: reddish-brown, tan, and grey; Luster: vitreous to waxy; Texture: preserves woody grain and cell structure; Cleavage: none (conchoidal fracture).

Formation & geological history

Formed when ancient trees were buried under sediment or volcanic ash, and minerals (usually silica) replaced the organic matter over millions of years through permineralization.

Uses & applications

Used for decorative items, jewelry (cabochons), interior design, and as a popular focus for geological collecting.

Geological facts

The process can perfectly preserve the tree's growth rings and even its cellular structure down to the microscopic level. Some specimens are over 200 million years old, dating back to the Triassic period.

Field identification & locations

Identified by its stone-like hardness combined with the visible grain or bark-like texture of wood; common in areas like the Petrified Forest National Park (Arizona) and similar arid desert regions.