mineral/sedimentary

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)

Hardness: 6.5-7 (Mohs scale), Color: tan-brown with waxy luster, Crystal structure: Microcrystalline quartz, Cleavage: None/Conchoidal fracture, Specific gravity: 2.6-2.9

Hardness: 6

Identified June 27, 2026More mineral/sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: tan-brown with waxy luster, Crystal structure: Microcrystalline quartz, Cleavage: None/Conchoidal fracture, Specific gravity: 2.6-2.9

Formation & geological history

Formed via permineralization during the late Mesozoic or Cenozoic, where organic wood tissue is replaced with silica in low-oxygen environments like volcanic ash or river floodplains.

Uses & applications

Used for decorative landscaping, jewelry (cabochons), interior design (tables/bookends), and educational museum collections.

Geological facts

This specimen displays a distinct cross-hatched or 'checking' pattern similar to the grain found in ancient trunks. If the cellular structure is perfectly preserved, it can be used to identify the specific species of extinct tree.

Field identification & locations

Identify by the presence of wood-like grain patterns and growth rings preserved in stone. Found globally in places like Arizona (Petrified Forest National Park) and Madagascar. Collectors look for bark preservation and vivid colors.

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