sedimentary

Fossiliferous Limestone

Biogenic Sedimentary Rock (Calcium Carbonate, CaCO3)

Hardness: 3 on Mohs scale; Color: Gray, tan, brown, or yellowish; Luster: Earthy to dull; Crystal structure: Trigonal (calcite); Cleavage: Perfect rhombohedral in calcite grains; Specific Gravity: 2.7 to 2.9

Hardness: 3 on Mohs scale
Color: Gray, tan, brown, or yellowish
Luster: Earthy to dull

Identified August 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the accumulation and lithification of organic debris such as shell fragments, crinoids, corals, and skeletal remains in shallow marine environments over millions of years, typically ranging from Paleozoic to Cenozoic eras.

Uses & applications

Used in construction as crushed stone, dimension stone, production of cement, agriculture to neutralize acidic soils, and highly valued by fossil collectors.

Geological facts

Fossiliferous limestone is a direct window into ancient marine ecosystems, frequently preserving remnants of prehistoric life such as brachiopods, bryozoans, and crinoid stems.

Field identification & locations

Identified easily by its reaction to dilute hydrochloric acid (effervescence/bubbling) and the visible presence of fossil fragments embedded in the matrix. Commonly found in marine sedimentary basins worldwide.

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Fossiliferous Concretion

Septarian Concretion containing Brachiopods/Crinoids

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Banded Siltstone / Mudstone Pebble

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