sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with Biogenic Fragments

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Grey, tan, buff, and light brown; Luster: Dull, earthy; Texture: Fine-grained matrix containing tiny fossil fragments such as crinoid stems, shell bits, or bryozoans.

Hardness: 3 on Mohs scale
Color: Grey, tan, buff, and light brown
Luster: Dull, earthy

Identified July 27, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in shallow, warm marine environments where biological debris like shells and skeletal fragments accumulated on the seafloor and underwent compaction and cementation over millions of years.

Uses & applications

Used in construction, lime production, aggregate, cement manufacturing, and popular as geological specimens and educational samples.

Geological facts

Fossiliferous limestone provides key evidence of ancient ocean conditions, shallow marine ecosystems, and past climate changes. Many major mountain ranges contain limestone pushed up from ancient ocean floors.

Field identification & locations

Identify by its reaction (fizzing) with dilute acid (HCl), softness compared to quartz, presence of small fossil impressions or rings, and earthy grey-tan coloration. Commonly found in riverbeds, limestone quarries, and sedimentary rock formations worldwide.