sedimentary
Fossiliferous Limestone (Shell Fragment)
Biogenic Limestone (Calcium Carbonate / CaCO3)
Hardness: 3 (Mohs scale); Color: Cream, tan, or white; Luster: Dull/Earthy; Structure: Clastic or organic aggregate; Specific Gravity: 2.3 - 2.7.
- Hardness
- 3 (Mohs scale)
- Color
- Cream, tan, or white
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3 (Mohs scale); Color: Cream, tan, or white; Luster: Dull/Earthy; Structure: Clastic or organic aggregate; Specific Gravity: 2.3 - 2.7.
Formation & geological history
Formed in marine or freshwater environments by the accumulation of organic debris such as shell, coral, and algae. Over millions of years, pressure and chemical cementation turns the sediment into rock.
Uses & applications
Used in construction as road base, in the manufacture of cement, as a soil conditioner in agriculture, and as a decorative stone.
Geological facts
Limestone covers about 10% of the Earth's land surface. This specific specimen appears to be an eroded piece of a bivalve or brachiopod shell that has undergone significant weathering and calcification.
Field identification & locations
Identify in the field by checking for a reaction (fizzing) when exposed to a weak acid like vinegar. Look for wavy growth lines and a porous texture. Often found in seafloors or ancient lakebeds.
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