sedimentary

Limestone with Fossil inclusions

Fossiliferous Limestone (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Grey with tan weathering; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None (rhombohedral in calcite crystals), reacts with HCl acid.

Hardness: 3 on Mohs scale
Color: Grey with tan weathering
Luster: Dull/Earthy

Identified May 22, 2026More sedimentary →

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Physical properties

Hardness: 3 on Mohs scale; Color: Grey with tan weathering; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None (rhombohedral in calcite crystals), reacts with HCl acid.

Formation & geological history

Formed in shallow marine environments from the accumulation of calcium carbonate and organic debris including shells, corals, and algae; typically Paleozoic to Cenozoic era.

Uses & applications

Crushed stone for road construction, lime for concrete, building facade material, and as an educational specimen for paleontology.

Geological facts

This specimen contains dark, rod-like impressions likely representing crinoid stems or small shell fragments. Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth.

Field identification & locations

Identify by its grey color, presence of visible fossil remains, and the 'fizz' test using vinegar or weak acid. Common in riverbeds and mountainous outcrops of former sea floors.