fossil

Fossil shell/brachiopod impression

Likely a fossil brachiopod (Phylum Brachiopoda), possibly a ribbed spiriferid; exact species requires examination

AI-generated identification · may be incorrect

Gray-tan, ribbed, fan-shaped specimen with sediment infill; likely calcitic shell material or a mold/cast. Original calcite has Mohs hardness about 3 and vitreous to dull luster; visible symmetry and radiating ribs are characteristic.

Identified August 16, 2026More fossil →

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At a glance

Common name: Fossil shell/brachiopod impression
Scientific name: Likely a fossil brachiopod (Phylum Brachiopoda), possibly a ribbed spiriferid; exact species requires examination
Category: fossil
Identified: August 16, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common small specimen; $50–$200+ if exceptionally preserved, prepared, or scientifically identified.

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

Formed when a marine shell was buried and preserved or dissolved, leaving a mold in limestone or shale. Brachiopods are especially common in Paleozoic rocks, roughly 541–252 million years old, though age cannot be determined from the photograph.

Uses & applications

Primarily a teaching, collecting, and decorative specimen; fossil brachiopods have little industrial value and are not generally used as gemstones.

Geological facts

Brachiopods resemble clams but have different shell symmetry: each valve is usually bilaterally symmetrical, unlike bivalves. Ribbed forms commonly inhabited shallow Paleozoic seas.

Field identification & locations

Look for a two-valved, bilaterally symmetrical shell, radiating ribs, a hinge line, and preservation in limestone or shale; dilute acid may fizz on exposed calcite. Common worldwide in Paleozoic sedimentary rocks, including North America, Europe, and Australia.