sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Hardness: 3 (Mohs scale); Color: Gray to light tan; Luster: Dull to earthy; Texture: Fine-grained matrix with visible fossil inclusions; Cleavage: None (conchoidal to irregular fracture).
- Hardness
- 3 (Mohs scale)
- Color
- Gray to light tan
- Luster
- Dull to earthy
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Physical properties
Hardness: 3 (Mohs scale); Color: Gray to light tan; Luster: Dull to earthy; Texture: Fine-grained matrix with visible fossil inclusions; Cleavage: None (conchoidal to irregular fracture).
Formation & geological history
Formed in marine environments through the accumulation of organic debris such as shell, coral, and algal fragments. Undergoes lithification over millions of years.
Uses & applications
Primary source of lime for cement, used as a building stone (dimension stone), crushed stone for road base, and common educational specimens for paleontology.
Geological facts
This specimen contains visible fossil impressions, possibly brachiopods or crinoids, which serve as 'time capsules' of ancient sea floors. It reacts vigorously (fizzes) with dilute hydrochloric acid.
Field identification & locations
Identify by looking for visible skeletal fragments or imprints of marine life within a gray, fine-grained rock. Use a drop of vinegar or acid to confirm carbonate composition.
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