sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3) - Limestone

Hardness: 3 on Mohs scale. Color: Light beige, tan, grey, or off-white. Luster: Dull, earthy, or crystalline. Texture: Fine-grained matrix containing fossil fragments or shell remnants. Reacts strongly with dilute hydrochloric acid.

Hardness: 3 on Mohs scale
Color: Light beige, tan, grey, or off-white
Luster: Dull, earthy, or crystalline

Identified July 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in shallow, warm marine or coastal environments through the accumulation and cementation of organic remains such as shells, coral fragments, and calcium carbonate precipitates. Often dates from Paleozoic to Cenozoic eras.

Uses & applications

Used in construction, aggregate for road building, production of cement and lime, soil conditioning in agriculture, and as decorative stone or landscaping material.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth. Fossiliferous varieties often contain ancient marine organisms like brachiopods, crinoids, bryozoans, or mollusks preserved in fine detail.

Field identification & locations

Identified by its tan/grey color, soft nature (easily scratched by a copper coin or steel blade), earthy texture, visible fossil/shell fragments, and effervescence with weak acids. Commonly found along coastal areas, ancient lakebeds, and karst landscapes.

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