fossil

Fossilized belemnite (likely a belemnite guard)

Belemnitida; a calcitic or originally aragonitic rostrum from an extinct marine cephalopod

AI-generated identification · may be incorrect

Elongate, bullet-shaped fossil with a brown weathered surface; belemnite guards are commonly calcite-replaced, Mohs hardness about 3, and lack visible crystal faces. Exact mineral composition and identity cannot be confirmed from the photograph alone.

Identified October 10, 2026More fossil →

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At a glance

Common name: Fossilized belemnite (likely a belemnite guard)
Scientific name: Belemnitida; a calcitic or originally aragonitic rostrum from an extinct marine cephalopod
Category: fossil
Identified: October 10, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common, modest specimen; larger, well-preserved or display-quality examples may sell for $30–$100 or more.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Belemnites lived in marine waters during the Mesozoic Era, especially the Jurassic and Cretaceous (about 201–66 million years ago). Their internal shell guards were buried in seafloor sediment and fossilized through mineral replacement.

Uses & applications

Primarily collected and displayed; fossils are also used in education and paleontological research.

Geological facts

Belemnites were squid-like cephalopods, and their bullet-shaped internal guards are among the most recognizable marine fossils.

Field identification & locations

Look for a tapered, solid, roughly conical guard, often with a pointed end and a small central cavity at the broader end. Belemnites occur in Mesozoic marine sedimentary rocks worldwide; the image suggests this form but does not show diagnostic details clearly.