Limestone

Limestone is a type of sedimentary rock that is primarily composed of calcium carbonate in the form of the mineral calcite. It also contains other materials such as clay, silt, and sand. Limestone is formed in clear, warm, shallow marine waters and is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal, and fecal debris.

Formation

Limestone is formed in two ways. It can be formed with the help of living organisms and by evaporation. Ocean-dwelling organisms such as oysters, clams, mussels and coral use calcium carbonate (CaCO3) from seawater to create their shells and bones. As these organisms die, their shells and bones are broken down by waves and settle on the ocean floor where they are compacted into limestone under pressure.

Types of Limestone

There are several different types of limestone, including travertine, oolitic limestone, and fossiliferous limestone. Travertine is a form of limestone deposited by mineral springs. Oolitic limestone is made up of small, spherical grains called ooids. Fossiliferous limestone is formed by remains of marine fossils.

Uses of Limestone

Limestone has numerous uses, including as a building material, as aggregate for the base of roads, as white pigment or filler in products such as toothpaste or paints, and as a chemical feedstock. It is also used in the manufacture of cement, brick, and concrete.

Environmental Impacts

The production of limestone can have negative impacts on the environment. The burning of limestone to create cement releases CO2 which contributes to climate change. In addition, mining operations can result in habitat destruction and contamination of surface water, groundwater, and soil.

See Also

• Sedimentary rock
• Calcium carbonate
• Cement
• Brick
• Concrete

Limestone Resources
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