Rock Identifier
Fossilized bivalve shell fragment (Fossil Mollusca, likely a pectinid or related bivalve; exact identification requires the other shell half and locality) — fossil
fossil

Fossilized bivalve shell fragment

Fossil Mollusca, likely a pectinid or related bivalve; exact identification requires the other shell half and locality

AI-generated identification · may be incorrect

Tan-brown, ribbed shell with visible radial ornamentation and layered calcite; mineralized shell material is mostly calcite (CaCO₃), Mohs hardness about 3, with dull to slightly pearly luster and prominent original growth ribs.

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Physical properties

Tan-brown, ribbed shell with visible radial ornamentation and layered calcite; mineralized shell material is mostly calcite (CaCO₃), Mohs hardness about 3, with dull to slightly pearly luster and prominent original growth ribs.

Formation & geological history

A marine bivalve shell was buried in sediment and preserved through compaction and mineral replacement, commonly during the Cenozoic or Mesozoic; the geological age cannot be determined from the image alone.

Uses & applications

Primarily a collectible and educational fossil; it has no significant industrial or jewelry use, though attractive polished fossil shells may be incorporated into ornaments.

Geological facts

Radial ribs and concentric growth lines are characteristic of many scallops and related bivalves. The apparent layered edge reflects shell growth and breakage rather than igneous crystal structure.

Field identification & locations

Identify it by its repeated radial ribs, curved shell geometry, and carbonate composition; it should fizz weakly in dilute hydrochloric acid unless heavily mineral-replaced. Common in marine limestone and coastal sedimentary deposits worldwide.

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