fossil

Fossilized bivalve in sandstone/conglomerate

Indeterminate fossil mollusk, likely Bivalvia, preserved in lithified siliciclastic sediment

AI-generated identification · may be incorrect

The shell is cream to tan, smooth, and weakly lustrous; surrounding rock is coarse, porous, and speckled with sand-sized grains and rounded pebbles. Shell calcite/aragonite has Mohs hardness about 3–4, while the host sandstone is typically 6–7; exact identification requires the hinge and shell ornamentation.

Identified September 10, 2026More fossil →

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At a glance

Common name: Fossilized bivalve in sandstone/conglomerate
Scientific name: Indeterminate fossil mollusk, likely Bivalvia, preserved in lithified siliciclastic sediment
Category: fossil
Identified: September 10, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common unprovenienced specimen; $50–$200+ if unusually complete, well-prepared, or from a documented locality.

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

A marine bivalve was buried in sediment, then mineralized and encased during compaction and cementation into sandstone or conglomerate. The specimen’s geological age cannot be determined from the image, but such fossils range from Paleozoic to Cenozoic deposits.

Uses & applications

Primarily a teaching, display, and collecting specimen; it has no meaningful industrial or jewelry use. Scientific value depends on locality, preservation, and taxonomic identification.

Geological facts

The large pale object appears to be a shell valve, with darker rounded grains or cavities in the host rock. Fossil shells may retain original carbonate or be replaced by calcite, silica, or iron-bearing minerals.

Field identification & locations

Look for bilateral shell symmetry, a hinge or umbo, growth lines, and consistent shell curvature; test the shell separately with dilute hydrochloric acid, which fizzes if carbonate remains. Common in marine sedimentary outcrops worldwide.