fossil
Sand Dollar (Fossilized or Calcium Carbonate Skeleton)
Clypeasteroida (Order)
Hardness: 2.5 - 3.5; Color: Off-white to tan; Luster: Dull or earthy; Structure: Fivefold radial symmetry (pentamerism); Composition: Calcium carbonate (calcite)
- Hardness
- 2
- Color
- Off-white to tan
- Luster
- Dull or earthy
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Physical properties
Hardness: 2.5 - 3.5; Color: Off-white to tan; Luster: Dull or earthy; Structure: Fivefold radial symmetry (pentamerism); Composition: Calcium carbonate (calcite)
Formation & geological history
Formed from the mineralized skeletal remains of sea urchins that live in shallow marine environments. While many found on beaches are recent, they frequently fossilize in sedimentary limestone and sandstone layers dating back to the Jurassic period.
Uses & applications
Primarily used for decorative purposes, jewelry, and educational collection. In fossilized form, they are valuable to paleontology.
Geological facts
The 'petals' on the surface are actually pores for respiratory feet. According to folklore, they represent the five wounds of Christ or coins lost by mermaids.
Field identification & locations
Identify by the circular flat disc shape and distinctive five-pointed star pattern. Commonly found on sandy coastlines or in ancient shallow marine sedimentary deposits.
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