fossil

Belemnite Fossil (Guardsman Fossil)

Belemnitella spp. (Rostrum)

Hardness of 3-4 on Mohs scale (composed of calcite), typically bullet or cigar-shaped, grey to brown in color, vitreous to dull luster, fibrous internal structure radiating from a central axis.

Identified August 5, 2026More fossil →

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Physical properties

Hardness of 3-4 on Mohs scale (composed of calcite), typically bullet or cigar-shaped, grey to brown in color, vitreous to dull luster, fibrous internal structure radiating from a central axis.

Formation & geological history

Formed during the Mesozoic era (Jurassic to Cretaceous periods, roughly 200 to 66 million years ago) when the hard, internal calcite shell (rostrum) of an extinct squid-like cephalopod became fossilized in marine sediments.

Uses & applications

Used primarily in fossil collecting, educational displays, and as index fossils for dating Mesozoic marine strata.

Geological facts

Belemnites were ancient relatives of modern squids and cuttlefish; in folklore, their bullet-shaped fossils were often called 'thunderbolts' or 'devil's fingers' because people believed they fell from the sky during lightning storms.

Field identification & locations

Easily identified by their distinctive bullet or cigar shape, symmetry, and the tiny central tube (alveulus) at the wider end. Often found weathered out of chalk cliffs, limestone, and marine sedimentary deposits across Europe and North America.

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