fossil

Petrified Wood

Silicified wood (primarily quartz, SiO2)

Hardness of 7 on the Mohs scale, earthy to vitreous luster, preserves original cellular wood structure, conchoidal fracture.

Identified November 12, 2026More fossil →

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Physical properties

Hardness of 7 on the Mohs scale, earthy to vitreous luster, preserves original cellular wood structure, conchoidal fracture.

Formed over millions of years when buried tree remains are saturated with mineral-rich groundwater, replacing organic matter with silica.

Used in decorative carvings, jewelry, lapidary arts, and highly prized by fossil and mineral collectors.

Famous deposits include the Petrified Forest National Park in Arizona, dating back over 200 million years to the Triassic period.

Identified by retaining distinct tree growth rings and bark textures while possessing the high weight and hardness of quartz.

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