sedimentary
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony replacing $SiO_2$)
Hardness: 6.5-7 on the Mohs scale, Color: Brown, reddish-brown, yellow, gray, black, Luster: Vitreous to dull, Crystal structure: Microcrystalline (quartz), Cleavage: None (conchoidal fracture), Specific Gravity: 2.5-2.7
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 on the Mohs scale, Color: Brown, reddish-brown, yellow, gray, black, Luster: Vitreous to dull, Crystal structure: Microcrystalline (quartz), Cleavage: None (conchoidal fracture), Specific Gravity: 2.5-2.7
Formation & geological history
Formed through permineralization, where organic wood material is buried under sediment in anoxic conditions and gradually replaced by minerals like silica-rich groundwater over millions of years (often Mesozoic or Cenozoic eras).
Uses & applications
Used in ornamental carvings, jewelry, lapidary arts, display specimens, and interior decor.
Geological facts
Petrified wood can preserve cellular structures of ancient trees down to the microscopic level, revealing details of prehistoric forests from millions of years ago.
Field identification & locations
Identify by retaining the external or internal wooden grain texture while having the cold, heavy, and extremely hard feel of solid stone. Found globally, especially in regions with ancient volcanic ash deposits.
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