Rock Identifier
Fossilized bone fragment (probable mammalian tooth or bone) (Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite) — fossil
fossil

Fossilized bone fragment (probable mammalian tooth or bone)

Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite

AI-generated identification · may be incorrect

Cream-yellow, layered and porous, with dark mineral staining; typically dull to waxy luster and no obvious crystal faces. Hardness is usually about 4–6 Mohs, depending on mineralization; specific gravity commonly 2.2–3.0.

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Physical properties

Cream-yellow, layered and porous, with dark mineral staining; typically dull to waxy luster and no obvious crystal faces. Hardness is usually about 4–6 Mohs, depending on mineralization; specific gravity commonly 2.2–3.0.

Formation & geological history

Originally biological bone or tooth, later buried and mineralized as groundwater replaced or filled organic tissues over thousands to millions of years; exact age and identity require microscopy or locality data.

Uses & applications

Primarily a collecting, educational, and paleontological specimen; exceptional identifiable fossils may be prepared for display.

Geological facts

The visible layered, irregular structure is more consistent with fossil bone or tooth than an igneous, sedimentary, or metamorphic rock. Yellow coloration commonly results from iron-oxide staining or diagenetic minerals.

Field identification & locations

Look for porous internal texture, biological layering, and irregular cortical surfaces; a fresh fracture may reveal distinctive bone canals or tooth enamel/dentine. Common in sedimentary deposits, river gravels, caves, and deserts; avoid acid or aggressive cleaning.