fossil

Fossilized echinoid (sea urchin), likely a sand dollar fragment or small regular urchin

Echinodermata; commonly Clypeasteroida or Echinoida, preserved mainly as calcite (CaCO₃)

AI-generated identification · may be incorrect

Hardness about 3 on Mohs scale; tan-beige, dull to slightly pearly luster, radial five-part symmetry, and porous calcitic structure. The central star-like petal pattern and radial grooves are characteristic of echinoid tests.

Identified August 26, 2026More fossil →

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At a glance

Common name: Fossilized echinoid (sea urchin), likely a sand dollar fragment or small regular urchin
Scientific name: Echinodermata; commonly Clypeasteroida or Echinoida, preserved mainly as calcite (CaCO₃)
Category: fossil
Identified: August 26, 2026
Method: Standard

AI Estimated Value

About $3-$20 for a small common example; $25-$100+ if complete, sharply patterned, unusually preserved, 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 echinoid skeleton, originally aragonite/calcite, was buried in carbonate sediment and fossilized through mineral preservation and compaction. Exact age cannot be determined from the image; specimens range from Paleozoic to Recent deposits.

Uses & applications

Primarily a fossil-collecting and educational specimen; intact examples are used in natural-history displays and jewelry or décor. It has little industrial value.

Geological facts

Echinoid tests are made of many interlocking calcite plates, often producing a distinctive five-petal ambulacral pattern. The specimen appears worn or partially mineralized rather than a complete modern shell.

Field identification & locations

Look for fivefold symmetry, repeated plate divisions, and radial petal zones; limestone matrix or chalky texture supports identification. Common in shallow-marine limestones and coastal sediments worldwide, including Florida, England, Morocco, and the Gulf Coast.