sedimentary
Fossiliferous Limestone (with Crinoids/Coral)
Fossiliferous Limestone (CaCO3)
Hardness: 3-4 (Mohs scale); Color: dark gray to brownish with white/tan fossil inclusions; Luster: dull to earthy; Texture: clastic/biogenic; Cleavage: none (conchoidal fracture).
- Hardness
- 3-4 (Mohs scale)
- Color
- dark gray to brownish with white/tan fossil inclusions
- Luster
- dull to earthy
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Physical properties
Hardness: 3-4 (Mohs scale); Color: dark gray to brownish with white/tan fossil inclusions; Luster: dull to earthy; Texture: clastic/biogenic; Cleavage: none (conchoidal fracture).
Formation & geological history
Formed in warm, shallow marine environments through the accumulation of calcium carbonate and biological remains like coral or crinoids during the Paleozoic era.
Uses & applications
Commonly used in construction, as a source for lime (cement), in landscaping, and as a popular specimen for fossil collectors.
Geological facts
Many of these rocks found in the Great Lakes region are 'pudding stones' or beach-worn fossils that have been tumbled smooth by glacial and wave action over thousands of years.
Field identification & locations
Look for visible white or cream-colored patterns against a darker matrix that look like rings, stars, or tubes. It react with dilute hydrochloric acid. It is commonly found on Great Lakes shorelines.
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