sedimentary

Fossiliferous Limestone

Carbonate sedimentary rock (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs scale), Color: Gray/beige/tan, Luster: Dull to earthy, Crystal Structure: Trigonal (microcrystalline calcite), Cleavage: Perfect rhombohedral in calcite crystals but often invisible in bulk rock.

Identified June 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in marine environments through the accumulation of shell, coral, algal, and fecal debris. Primarily associated with shallow tropical or subtropical seas throughout various geological ages (Paleozoic to modern).

Uses & applications

Used extensively in construction (aggregate, cement, building stones), as a soil conditioner in agriculture, and small fossiliferous pieces are popular in educational collections.

Geological facts

Limestone accounts for about 10% of the total volume of all sedimentary rocks. Many specimens contain visible ancient sea creatures like crinoids, shells, or coral fragments.

Field identification & locations

Identify by looking for visible fossil imprints or shell fragments; reacts with a fizzing sound when a drop of dilute hydrochloric acid (or vinegar) is applied. Found worldwide in former sea beds.