sedimentary

Limestone

Calcareous sedimentary rock (CaCO3)

AI-generated identification · may be incorrect

Hardness 3 on Mohs scale; typically white, gray, or tan; dull to earthy luster; fine-grained to coarse-grained crystal structure; reacts strongly with dilute hydrochloric acid.

Identified November 15, 2026More sedimentary →

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Physical properties

Hardness 3 on Mohs scale; typically white, gray, or tan; dull to earthy luster; fine-grained to coarse-grained crystal structure; reacts strongly with dilute hydrochloric acid.

Formation & geological history

Formed through the accumulation of skeletal fragments from marine organisms like coral, mollusks, and foraminifera, or via chemical precipitation in shallow marine environments over millions of years.

Uses & applications

Extensively used in construction as building stone, as aggregate in road base, in the production of cement, and in agriculture to neutralize acidic soils.

Geological facts

Limestone frequently contains well-preserved fossils and forms dramatic landscapes known as karst topography, featuring caves, sinkholes, and underground drainage systems.

Field identification & locations

Easily identified by its soft nature, reaction to acid, and typical light gray or tan coloring. Found worldwide in regions with ancient shallow sea history.