sedimentary
Limestone (Fossiliferous)
Sedimentary Carbonate Rock (CaCO3)
Hardness: 3 on Mohs scale; Color: Gray to tan; Luster: Dull or earthy; Structure: Clastic or biogenic with fine-grained matrix; Cleavage: None (conchoidal to irregular fracture); Specific Gravity: 2.5-2.7
- Hardness
- 3 on Mohs scale
- Color
- Gray to tan
- Luster
- Dull or earthy
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Physical properties
Hardness: 3 on Mohs scale; Color: Gray to tan; Luster: Dull or earthy; Structure: Clastic or biogenic with fine-grained matrix; Cleavage: None (conchoidal to irregular fracture); Specific Gravity: 2.5-2.7
Formation & geological history
Formed in shallow marine environments from the accumulation of calcium carbonate and organic debris. These slabs often originate from the Paleozoic era (approx. 300-500 million years ago) via lithification of marine sediments.
Uses & applications
Used widely in construction as flagstone, road base, and raw material for cement. High-quality slabs are used for architectural cladding or landscaping. Richly fossiliferous pieces are kept by collectors.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It often contains preserved traces of ancient life, such as crinoids, brachiopods, or ichnofossils (trace fossils).
Field identification & locations
Identify by applying a small amount of household vinegar; it will effervesce (fizzle) due to the calcium carbonate content. Commonly found in former seabed regions. Look for bedding planes and visible fossil fragments.
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