sedimentary
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, reddish, and gray; Luster: Waxy to vitreous; Crystal structure: Cryptocrystalline; Cleavage: None; Specific Gravity: 2.6-2.9.
- Hardness
- 6
- Color
- Brown, tan, reddish, and gray
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, reddish, and gray; Luster: Waxy to vitreous; Crystal structure: Cryptocrystalline; Cleavage: None; Specific Gravity: 2.6-2.9.
Formation & geological history
Formed through permineralization where organic wood materials are replaced by silica-rich minerals (often from volcanic ash) over millions of years. Common in Triassic to Tertiary deposits.
Uses & applications
Used for ornamental furniture, high-end interior design slabs, lapidary art, jewelry, and as a popular collector's specimen.
Geological facts
Famous locations include the Petrified Forest National Park in Arizona. It is a 'body fossil' where the original cellular structure is often preserved in stone.
Field identification & locations
Identified by its wood-like texture and growth rings preserved in a hard, stony material. Commonly found in sedimentary basins and areas with historical volcanic activity.
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