fossil
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
Hardness: 3-4 (Calcite matrix). Color: Rusty reddish-brown exterior (Iron oxides), tan to grey interior. Luster: Dull, earthy. Structure: Sedimentary nodule containing marine imprints.
- Hardness
- 3-4 (Calcite matrix)
- Luster
- Dull, earthy
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Physical properties
Hardness: 3-4 (Calcite matrix). Color: Rusty reddish-brown exterior (Iron oxides), tan to grey interior. Luster: Dull, earthy. Structure: Sedimentary nodule containing marine imprints.
Formation & geological history
Formed during the Paleozoic era by the accumulation of minerals around a biological nucleus in soft sediment, later hardening into a nodule. Often millions of years old.
Uses & applications
Educational specimens, fossil collecting, and decorative display.
Geological facts
Concretions are often mistaken for dinosaur eggs or meteorites due to their round, unusual shapes. This specimen specifically shows marine fauna preserved in a sedimentary matrix.
Field identification & locations
Identify by looking for distinct biological patterns (ribbed shells/columns) embedded in a different rock matrix. Commonly found in shale or limestone outcrops near ancient sea beds.
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