fossil

Sand dollar fossil

Clypeasteroida (echinoid test), commonly Clypeasteroides spp.

AI-generated identification · may be incorrect

A pale, disc-shaped calcareous skeleton with a five-petaled ambulacral pattern; composed mainly of porous calcite. Mohs hardness is about 3–4, with a dull to softly pearly luster and fragile structure; it may be intact or naturally beach-worn.

Identified September 4, 2026More fossil →

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Physical properties

Formation & geological history

This is the test (skeleton) of a marine echinoid, preserved as biogenic calcite in shallow coastal sediments. Most modern-looking specimens are geologically young—Quaternary to Recent, generally younger than 2.6 million years.

Uses & applications

Primarily a collectible, educational specimen, or decorative beach find; powdered fossil tests have little practical industrial use compared with limestone.

Geological facts

The five-petal design represents the animal’s feeding and respiratory structures, while the small dove-like markings sometimes visible on the underside inspired Christian folklore.

Field identification & locations

Common on sandy beaches and fossil-bearing coastal deposits worldwide, especially Florida, the Gulf Coast, the Caribbean, and the Mediterranean. Identify it by the symmetrical five-petal pattern, porous chalky calcite, and flat round form.