mineral
Petrified Wood
Silicified Wood (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7.0 on Mohs scale; Color: Variable (brown, tan, black, grey, red); Luster: Vitreous to waxy; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.9
- Hardness
- 6
- Color
- Variable (brown, tan, black, grey, red)
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7.0 on Mohs scale; Color: Variable (brown, tan, black, grey, red); Luster: Vitreous to waxy; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.9
Formation & geological history
Formed through permineralization where organic wood materials are replaced by minerals (usually silica) over millions of years. This specimen often dates from the Triassic, Jurassic, or Cretaceous periods.
Uses & applications
Used for jewelry (cabochons), interior decor (tabletops, bookends), and as collector specimens in mineralogy and paleontology.
Geological facts
Petrified wood is the state gem of Washington and the state fossil of Arizona. It preserves the microscopic cellular structure of the original tree despite being entirely stone.
Field identification & locations
Identify by looking for bark textures and growth rings preserved in stone. Found globally in ancient sedimentary basins like Arizona's Petrified Forest or the Egyptian deserts. Collectors look for high polish and vibrant color retention.
