sedimentary
Fossiliferous Limestone
Calcite (CaCO3) with Bioclastic inclusions
Hardness: 3 on Mohs scale; Color: Cream, tan, or grey; Luster: Dull/Earthy; Crystal Structure: Hexagonal (microcrystalline calcite matrix); Cleavage: Perfect rhombohedral in calcite crystals, though generally massive; Specific Gravity: 2.71.
- Hardness
- 3 on Mohs scale
- Color
- Cream, tan, or grey
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3 on Mohs scale; Color: Cream, tan, or grey; Luster: Dull/Earthy; Crystal Structure: Hexagonal (microcrystalline calcite matrix); Cleavage: Perfect rhombohedral in calcite crystals, though generally massive; Specific Gravity: 2.71.
Formation & geological history
Formed in shallow, warm marine environments through the accumulation of organic debris such as shell fragments, coral, and algae. The geological age of such specimens typically ranges from the Paleozoic to the Cenozoic era.
Uses & applications
Used widely in the construction industry as building stone, road base, and in the production of cement and lime. It is also used as an agricultural soil conditioner.
Geological facts
Limestone covers about 10% of the Earth's total land surface. Notable structures built with limestone include the Great Pyramids of Giza. Many limestone deposits contain complete marine fossils like brachiopods and crinoids.
Field identification & locations
Identify in the field by its light color and the presence of visible fossil fragments or 'imprints.' It will vigorously effervesce (fizz) when exposed to a drop of dilute hydrochloric acid. It is commonly found in areas that were once prehistoric seafloors.
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