fossil

Petrified Wood

Silicified wood (Quartz pseudomorph after wood)

Mohs hardness of 7, vitreous to dull luster, cryptocrystalline quartz structure, and retains the fibrous grain texture of original wood.

Identified October 23, 2026More fossil →

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Physical properties

Mohs hardness of 7, vitreous to dull luster, cryptocrystalline quartz structure, and retains the fibrous grain texture of original wood.

Formed via permineralization where groundwater rich in dissolved silica replaces organic wood cellular structure over millions of years.

Used for ornamental carvings, decorative tabletops, jewelry, and prized by fossil collectors.

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

Identify by wood-like exterior bark texture combined with heavy weight and conchoidal fracture of quartz; found worldwide in sedimentary rock layers.

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