Limestone | Characteristics, Formation, Texture, Uses, & Facts (2024)

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What is limestone made of?

Limestone is a sedimentary rock made of calcium carbonate (CaCO₃), usually in the form of calcite or aragonite. It may contain considerable amounts of magnesium carbonate (dolomite) as well. However, minor constituents of clay, iron carbonate, feldspar, pyrite, and quartz is also commonly present. In many cases, the grains are microscopic fragments of fossil animal shells.

What are the uses of limestone?

Limestone is used extensively in road and building construction, and is a material found in aggregate, cement, building stones, chalk, and crushed stone.

What important compound does limestone yield?

Limestone is a source of lime (calcium oxide), which is used in steel manufacturing, mining, paper production, water treatment and purification, and plastic production.Lime also has major applications in the manufacture of glass and in agriculture.

How does limestone form?

Limestone originates mainly through the lithification of loose carbonate sediments. Modern carbonate sediments are generated in a variety of environments: continental, marine, and transitional, but most are marine. The present-day Bahama banks is the best known modern carbonate setting.

Why is limestone of interest to paleontologists and earth scientists?

Limestone is rich in fossil content. Much knowledge of the Earth’s chronology and development has been derived from the study of fossils embedded in limestone and other carbonate rocks.

limestone, sedimentary rock composed mainly of calcium carbonate (CaCO₃), usually in the form of calcite or aragonite. It may contain considerable amounts of magnesium carbonate (dolomite) as well; minor constituents also commonly present include clay, iron carbonate, feldspar, pyrite, and quartz.

Most limestones have a granular texture. Their constituent grains range in size from 0.001 mm (0.00004 inch) to visible particles. In many cases, the grains are microscopic fragments of fossil animal shells.

Britannica Quiz(Bed) Rocks and (Flint) Stones

Limestone has two origins: (1) biogenic precipitation from seawater, the primary agents being lime-secreting organisms and foraminifera; and (2) mechanical transport and deposition of preexisting limestones, forming clastic deposits. Travertine, tufa, caliche, chalk, sparite, and micrite are all varieties of limestone.

Limestone has long fascinated earth scientists because of its rich fossil content. Much knowledge of the Earth’s chronology and development has been derived from the study of fossils embedded in limestone and other carbonate rocks. Limestone also has considerable commercial importance. Limestones enriched in phosphate by the chemical action of ocean waters constitute a principal source of raw materials for the fertilizer industry. When heated to temperatures of 900 to 1,000 °C (1,650 to 1,800 °F), limestones will dissociate calcium carbonate and yield carbon dioxide and lime, the latter having major applications in the manufacture of glass and in agriculture. Certain varieties of limestone also serve as a building stone; they are widely used for flooring, exterior and interior facings, and monuments.

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Adam Augustyn.