sedimentary

Limestone

Carbonate Rock (predominantly Calcite, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 on the Mohs scale; Color: Light beige, buff, cream, or off-white; Luster: Dull, earthy; Texture: Fine to medium-grained with small bioclasts and crystalline calcite patches; Specific Gravity: 2.3 - 2.7.

Hardness: 3 on the Mohs scale
Color: Light beige, buff, cream, or off-white
Luster: Dull, earthy

Identified October 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation, compaction, and cementation of marine organism debris (shells, coral, algae) and chemical precipitation of calcium carbonate in warm, shallow, calm marine environments over millions of years.

Uses & applications

Extensively used in construction as crushed stone aggregate, building stone, raw material for Portland cement, lime production, soil treatment in agriculture, and neutralizer in chemical processes.

Geological facts

Limestone comprises about 10% of the total volume of all sedimentary rocks on Earth. Famous monuments like the Great Pyramids of Giza and many iconic European cathedrals are built entirely from limestone. It dissolves easily in mildly acidic water, creating spectacular karst landscapes, sinkholes, and underground caves.

Field identification & locations

Easily identified in the field by vigorous effervescence (fizzing) when exposed to dilute hydrochloric acid (HCl), and can be scratched easily with a copper penny or steel blade. Extremely common globally in sedimentary basins, road cuts, and coastal outcrops.