sedimentary

Fossiliferous Limestone

Bioclastic Limestone (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs scale), Color: Cream, tan, or gray with visible shell fragments, Luster: Dull or earthy, Structure: Clastic or organic sedimentary texture. Highly reactive to dilute Hydrochloric Acid.

Identified July 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in shallow, warm marine environments through the accumulation of skeletal remains of organisms like corals, brachiopods, and mollusks over millions of years. Common in Paleozoic to Cenozoic strata.

Uses & applications

Used extensively in the manufacture of cement and lime, as road base material, in chemical processing, and as building stone. Often collected for decorative architectural veneer.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. The Great Pyramids of Giza were originally encased in polished casing stones of high-quality limestone.

Field identification & locations

Identified by visible shell/fossil imprints and its softness relative to steel. Found globally in coastal areas or regions that were once prehistoric seafloors. Collectors should look for distinct shell patterns.