Rock Identifier
Weathered fossil fragment, possibly bone (Indeterminate fossilized bone; likely mineralized vertebrate bone (apatite-rich)) — fossil
fossil

Weathered fossil fragment, possibly bone

Indeterminate fossilized bone; likely mineralized vertebrate bone (apatite-rich)

AI-generated identification · may be incorrect

Tan to brown, porous and irregular, with a rough earthy luster and possible fibrous or cellular texture. Mineralized bone commonly has Mohs hardness about 4–5 and specific gravity around 2.8–3.2; exact properties depend on replacement minerals.

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Physical properties

Tan to brown, porous and irregular, with a rough earthy luster and possible fibrous or cellular texture. Mineralized bone commonly has Mohs hardness about 4–5 and specific gravity around 2.8–3.2; exact properties depend on replacement minerals.

Formation & geological history

Formed when buried bone was preserved and gradually mineralized by groundwater, commonly during sediment deposition and diagenesis; its geological age cannot be determined from the photograph. The surface appears weathered and water-worn.

Uses & applications

Primarily a geological or educational specimen; attractive pieces may be collected, but it has no typical industrial or jewelry use. Avoid acid testing or destructive preparation if provenance is unknown.

Geological facts

The apparent small pores and layered, organic-looking texture are more consistent with fossil bone than with an ordinary rock, though shell or weathered limestone is also possible.

Field identification & locations

Commonly found in stream gravels, sedimentary exposures, and eroding badlands. A close inspection for repeating cellular pores, dense outer cortex, and a sharp contrast between interior and exterior can help distinguish bone from limestone; laboratory analysis is needed for certainty.

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

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

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Porous limestone pebble

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

sedimentary
Weathered fossil bone fragment (identification uncertain) (Fossilized bone; exact taxon and mineral composition cannot be determined from the image) — fossil

Weathered fossil bone fragment (identification uncertain)

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

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