mineral

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Brown, tan, red, and grey tones due to mineral impurities like iron and manganese; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9

Hardness: 6
Luster: Waxy to dull

Identified May 31, 2026More mineral →

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Physical properties

Formation & geological history

Formed through permineralization where organic wood material is replaced by minerals, typically silica from volcanic ash, over millions of years. Most common specimens date from the Devonian to the Holocene epochs.

Uses & applications

Used for ornamental furniture, jewelry (cabochons), interior design, and as highly collectible geological specimens.

Geological facts

Petrified wood is the state stone of Arizona. Entire forests, such as the Petrified Forest National Park, have been preserved in stone, capturing cellular-level detail of ancient trees.

Field identification & locations

Identify in the field by looking for bark-like textures, growth rings, and wood grain patterns on a heavy, stone-hard material. Found globally in areas with ancient volcanic activity and sedimentary basins.

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