sedimentary
Fossiliferous Limestone
Fossiliferous Calcarenite (CaCO3)
Hardness: 3 on Mohs scale; Color: Cream, tan, or grey; Luster: Dull to earthy; Structure: Clastic or biogenic with visible fossil clasts; Reacts strongly with dilute HCl acid.
- Hardness
- 3 on Mohs scale
- Color
- Cream, tan, or grey
- Luster
- Dull to earthy
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Physical properties
Hardness: 3 on Mohs scale; Color: Cream, tan, or grey; Luster: Dull to earthy; Structure: Clastic or biogenic with visible fossil clasts; Reacts strongly with dilute HCl acid.
Formation & geological history
Formed in marine environments through the accumulation of calcium carbonate shells, skeletal fragments, and coral debris that are later cemented together during lithification. Most dates from the Phanerozoic eon.
Uses & applications
Used in construction as a building stone or aggregate, as a source for lime (calcium oxide) in agricultural and industrial processes, and as a popular specimen for educational fossil collecting.
Geological facts
This specific piece is coquina-like, containing gastropod or bivalve shells. Large portions of the Great Pyramids of Giza are constructed from fossiliferous nummulitic limestone.
Field identification & locations
Look for visible sea shells or fragments embedded in a fine-grained, light-colored matrix. Common in coastal regions or areas that were ancient sea beds. Soft enough to be scratched by a steel nail.
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