sedimentary
Echinoidea (Fossil Sea Urchin)
Echinodermata Echinoidea
Hardness: 3-4 (calcite composition); Color: Cream, light brown, or tan; Luster: Dull or earthy; Structure: Five-fold radial symmetry (pentamerism) with visible pore paths.
- Hardness
- 3-4 (calcite composition)
- Color
- Cream, light brown, or tan
- Luster
- Dull or earthy
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Physical properties
Hardness: 3-4 (calcite composition); Color: Cream, light brown, or tan; Luster: Dull or earthy; Structure: Five-fold radial symmetry (pentamerism) with visible pore paths.
Formation & geological history
Formed during the Mesozoic or Cenozoic eras (approx. 66-145 million years ago) in shallow marine environments where the organism was buried in seafloor sediment and mineralized.
Uses & applications
Paleontological study, educational specimen, and collector item.
Geological facts
These are often called 'lucky stones' or 'fairy loaves'. They belong to the same group as modern-day sea urchins and sand dollars.
Field identification & locations
Look for pentagonal symmetry or star-shaped patterns on the surface. Commonly found in limestone outcrops, chalk beds, or coastal erosion areas.
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