mineral

Petrified Wood

Silicified Wood (primarily SiO2)

Hardness: 6.5-7 Mohs; Color: Brown, tan, red, and grey; Luster: Waxy to vitreous; Crystal Structure: Amorphous/Cryptocrystalline; Cleavage: None; Specific Gravity: 2.6-2.9

Hardness: 6
Color: Brown, tan, red, and grey
Luster: Waxy to vitreous

Identified May 25, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Brown, tan, red, and grey; Luster: Waxy to vitreous; Crystal Structure: Amorphous/Cryptocrystalline; Cleavage: None; Specific Gravity: 2.6-2.9

Formation & geological history

Formed through permineralization, a process where organic material is replaced by minerals (usually silica) while retaining the original tree structure. This specimen likely dates from the Triassic to the Neogene periods.

Uses & applications

Used primarily for decorative furniture, jewelry cabochons, lapidary arts, and as a popular collector's specimen.

Geological facts

The 'petrified' process happens deep underground without oxygen, preventing aerobic decomposition. Entire forests of these exist in places like Arizona, where trees were buried by volcanic ash.

Field identification & locations

Identify in the field by looking for bark textures, growth rings, or cellular structures preserved in stone. Found globally in areas with ancient volcanic activity and sedimentary basins.