fossil

Fossilized bone fragment

Petrified vertebrate bone; mineralized hydroxyapatite replaced or infilled by silica/carbonates

AI-generated identification · may be incorrect

Dense, elongated fragment with a dark mineralized outer cortex and lighter porous internal bone; typically Mohs 4–7, dull to slightly waxy luster, with preserved fibrous/vascular structure rather than crystal faces.

Identified September 12, 2026More fossil →

Explore Fossilized bone fragment in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

A vertebrate bone buried in sediment was progressively mineralized during diagenesis, commonly in the Mesozoic or Cenozoic; exact age and species require locality and laboratory analysis.

Uses & applications

Primarily a collecting, educational, and research specimen; attractive polished pieces may be used decoratively, but it has little industrial value.

Geological facts

The visible layered structure resembles cortical bone surrounding cancellous or medullary bone. Color commonly reflects iron, manganese, silica, or organic-mineral alteration.

Field identification & locations

Identify by checking for a repeated vascular/porous pattern, cortical–medullary layering, unusual density, and mineral-filled cavities; common sources include sedimentary basins and river gravels in the western United States, Madagascar, and Mongolia.