sedimentary

Fossilized Bone Fragment

Permineralized Vertebrate Fossil (Hydroxyapatite replaced by Minerals)

Hardness: 5 (Mohs scale), Color: tan to light brown with lighter porous center, Luster: dull to earthy, Structure: vesicular/porous marrow interior with dense cortical exterior, Cleavage: none (irregular fracture).

Identified March 9, 2026More sedimentary →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed through permineralization where mineral-rich water fills the pores of organic bone material. These are found in sedimentary rock layers ranging from the Paleozoic to the Cenozoic era, typically in fluvial or lacustrine environments.

Uses & applications

Used primarily for scientific research (paleontology), educational purposes, and by hobbyist mineral collectors.

Geological facts

Small fragments like this are often referred to as 'chunk-o-saurus' by paleontologists when they are too weathered to identify the specific species. The 'tongue test' is often used by collectors; porous fossilized bone will stick slightly to the tongue due to capillary action.

Field identification & locations

Identify in the field by looking for 'honeycomb' or porous textures inside a smooth outer shell. Commonly found in badlands, riverbeds, and construction sites cutting through sedimentary basins. Collectors should look for internal cell structure.

Other sedimentary specimens

See all

Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary

Shale or Slaty Mudstone

Argillaceous sedimentary rock

sedimentary

Chert Breccia

Brecciated Chert (Microcrystalline Silica)

sedimentary

Sandstone (Quartz-rich)

Arenite (SiO2)

sedimentary

Sandstone (with man-made markings)

Arenite (composed primarily of Quartz, SiO2)

sedimentary