sedimentary

Fossiliferous Limestone

Biogenic Sedimentary Rock (Calcite, CaCO3)

Hardness of 3 on the Mohs scale; color ranges from light gray, tan, to yellowish-brown; luster is typically dull to earthy; composed primarily of calcium carbonate with visible fossil fragments such as brachiopods, crinoids, and mollusks; good effervescence when tested with dilute hydrochloric acid.

Identified August 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in marine environments through the accumulation and compaction of shell, coral, algal, and fecal debris over millions of years, often dating from the Paleozoic to Cenozoic eras.

Uses & applications

Used widely in the construction industry as crushed stone for road base, concrete aggregate, dimension stone for buildings, and as a raw material in the manufacture of cement and agricultural lime.

Geological facts

Fossiliferous limestone preserves the skeletal remains of ancient shallow-marine life, making it a valuable archive of earth's evolutionary and paleoenvironmental history.

Field identification & locations

Easily identified in the field by its reaction to acid (fizzing) and the visible presence of fossil molds and casts embedded in the rock matrix; commonly found in sedimentary basins worldwide.

Other sedimentary specimens

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Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Fossiliferous Concretion

Septarian Concretion containing Brachiopods/Crinoids

fossil

Quartz pebble

Silicon dioxide (SiO2)

sedimentary

Generic Pebble / Rock Fragment

Lithic fragment / Weathered rock

sedimentary

Sedimentary Sandstone

Arenite (Sedimentary Rock)

sedimentary

Banded Siltstone / Mudstone Pebble

Siltstone / Argillite

sedimentary