fossil
Petrified Wood Fragment
Silicified Wood (SiO2)
Hardness 6.5-7 on Mohs scale; light brown, tan, and reddish hues; vitreous to dull luster; retains organic wood grain cellular structures now replaced by microcrystalline quartz.
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Physical properties
Hardness 6.5-7 on Mohs scale; light brown, tan, and reddish hues; vitreous to dull luster; retains organic wood grain cellular structures now replaced by microcrystalline quartz.
Formation & geological history
Formed when plant material is buried under sediment or volcanic ash, saturated with mineral-rich groundwater, replacing organic plant cells with silica over millions of years (typically Triassic to Eocene epoch).
Uses & applications
Used for lapidary arts, jewelry, decorative polished displays, and general fossil collections.
Geological facts
Petrified wood is the state fossil of Washington and Mississippi; complete ancient trees can remain perfectly preserved in minute cellular detail.
Field identification & locations
Look for fibrous wood grain patterns combined with the hardness and weight of stone. Commonly found in ancient riverbeds, sedimentary basins, and volcanic terrain such as Arizona, Oregon, and Madagascar.
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