fossil

Fossilized belemnite guard (likely)

Belemnitella or related belemnite; fossil calcite (CaCO₃)

AI-generated identification · may be incorrect

A tapered, bullet-shaped brown specimen with a longitudinal groove and broken end, consistent with a belemnite rostrum. Calcite has Mohs hardness 3, vitreous to dull luster, poor cleavage, and specific gravity about 2.7; weathered surfaces may be brown from iron oxides.

Identified September 15, 2026More fossil →

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Physical properties

Formation & geological history

Belemnites were extinct marine cephalopods whose internal bullet-shaped guards fossilized through burial and mineral preservation, commonly during the Jurassic–Cretaceous (about 201–66 million years ago).

Uses & applications

Primarily a teaching, collecting, and decorative fossil; it has no significant industrial use, though calcite fossils may be cut or polished.

Geological facts

Belemnite guards are commonly mistaken for bullets or dinosaur bones. Their tapered shape and radial internal structure reflect the animal’s internal support organ, not a shell.

Field identification & locations

Look for a tapered, symmetrical form, calcitic texture, and a distinctive internal cone or radial structure at a broken end. Common in Jurassic and Cretaceous marine rocks, especially in Europe and North America.