fossil

Petrified Wood

Silicified Wood (SiO2)

Hardness of 7 on Mohs scale; displays preserved wood grain patterns in brown, tan, and reddish hues; vitreous to dull luster.

Identified October 22, 2026More fossil →

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Physical properties

Hardness of 7 on Mohs scale; displays preserved wood grain patterns in brown, tan, and reddish hues; vitreous to dull luster.

Formed through permineralization where organic material in buried wood is gradually replaced by silica-rich groundwater over millions of years.

Used in decorative carvings, lapidary arts, high-end jewelry, and as collector specimens.

Famous occurrences include the Petrified Forest National Park in Arizona, containing trees dating back over 200 million years.

Identify by its heavy weight, conchoidal fracture, and microscopic cellular structures visible under magnification.

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image