sedimentary
Fossilized Sea Urchin (Echinoid)
Echinoidea (Fossil specimen, often replaced by Calcite or Silica)
Hardness: 3 (if calcite replacement); Color: Cream, tan, or white; Luster: Dull/Earthy; Structure: Five-fold pentameral symmetry (petaloid pattern); No cleavage.
- Hardness
- 3 (if calcite replacement)
- Color
- Cream, tan, or white
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3 (if calcite replacement); Color: Cream, tan, or white; Luster: Dull/Earthy; Structure: Five-fold pentameral symmetry (petaloid pattern); No cleavage.
Formation & geological history
Formed through the permineralization of marine echinoids in shallow sea environments; typically found in limestone or chalk deposits ranging from the Jurassic to the Cretaceous periods.
Uses & applications
Used primarily as decorative collector specimens, educational study material in paleontology, and occasionally as jewelry components.
Geological facts
Also known as 'fairy loaves' or 'shepherd's crowns' in folklore. They represent the hard skeleton (test) of ancient sea urchins preserved over millions of years.
Field identification & locations
Identify in the field by looking for the distinct 'star' or petal pattern on rounded, stony nodules in sedimentary outcrops. Common in the chalk cliffs of Europe and desert regions of Northern Africa and North America.
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