fossil

Echinoid Fossil / Fossilized Sea Urchin

Echinoidea

Hardness typically around 3-4 (calcite), color ranges from tan, brown, to grey, dull to earthy luster, calcite crystal structure often preserving internal matrix or flint/chert replacement.

Identified August 2, 2026More fossil →

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Physical properties

Hardness typically around 3-4 (calcite), color ranges from tan, brown, to grey, dull to earthy luster, calcite crystal structure often preserving internal matrix or flint/chert replacement.

Formation & geological history

Formed through the fossilization of prehistoric marine echinoids, typically during the Cretaceous or Jurassic periods, where the skeletal remains (test) were buried in sediment and replaced by minerals like silica or calcite.

Uses & applications

Valuable for paleontological study, educational displays, and as unique collector items.

Geological facts

Often referred to colloquially by historical names like 'fairy loaves' or 'shepherd's stones', these fossils are frequently found weathered out of chalk cliffs and limestone formations.

Field identification & locations

Look for a characteristic pentameral (five-part) symmetry pattern on the top or bottom surface, commonly found in sedimentary limestone or chalk deposits near coastlines.