sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with organic fossil inclusions

Hardness: 3 on Mohs scale; Color: Off-white, beige, light tan, grey; Luster: Dull, earthy; Texture: Fine-grained matrix with visible fossil/shell fragments; Cleavage: None (conchoidal to uneven fracture); Specific Gravity: 2.5-2.7

Hardness: 3 on Mohs scale
Color: Off-white, beige, light tan, grey
Luster: Dull, earthy

Identified July 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in shallow, warm marine environments where biological debris, primarily carbonate shells and marine organism fragments, accumulated over millions of years and underwent compaction and cementation.

Uses & applications

Widely used as building stone, gravel aggregate, lime production in agriculture, cement manufacturing, and as decorative landscape stone. Collector specimens are prized for visible fossil content.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It dissolves slowly in weak acid, which causes dramatic karst landscapes, caves, and sinkholes around the world.

Field identification & locations

Can be easily identified by its light color, soft texture (scratched easily with a steel nail), and strong fizzing reaction (effervescence) when exposed to cold dilute hydrochloric acid or vinegar. Commonly found in ancient sea beds worldwide.

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