sedimentary
Petrified Wood
Silicified Wood (SiO2)
Hardness of 7 on the Mohs scale, colors include brown, red, yellow, and grey, luster is vitreous to dull, crystal structure is microcrystalline quartz (chalcedony/jasper), specific gravity ranges from 2.5 to 2.8.
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Physical properties
Hardness of 7 on the Mohs scale, colors include brown, red, yellow, and grey, luster is vitreous to dull, crystal structure is microcrystalline quartz (chalcedony/jasper), specific gravity ranges from 2.5 to 2.8.
Formation & geological history
Formed when fallen trees are rapidly buried in low-oxygen, sediment-rich environments such as river floodplains or volcanic ash beds, allowing mineral-rich groundwater to slowly replace organic material with silica over millions of years.
Uses & applications
Used for ornamental objects, high-end lapidary work, decorative tabletops, landscaping, and by collectors.
Geological facts
Petrified wood preserves the original cellular structure of the ancient trees, sometimes showing detailed annual growth rings and bark texture.
Field identification & locations
Found worldwide in sedimentary layers and volcanic deposits, often identified by its distinct wood-like external shape combined with the heavy, rock-like feel and conchoidal fracture of quartz.
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