sedimentary

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale); Color: Gray to light tan; Luster: Dull to earthy; Texture: Fine-grained matrix with visible fossil inclusions; Cleavage: None (conchoidal to irregular fracture).

Hardness: 3 (Mohs scale)
Color: Gray to light tan
Luster: Dull to earthy

Identified April 4, 2026More sedimentary →

Explore Fossiliferous Limestone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 3 (Mohs scale); Color: Gray to light tan; Luster: Dull to earthy; Texture: Fine-grained matrix with visible fossil inclusions; Cleavage: None (conchoidal to irregular fracture).

Formation & geological history

Formed in marine environments through the accumulation of organic debris such as shell, coral, and algal fragments. Undergoes lithification over millions of years.

Uses & applications

Primary source of lime for cement, used as a building stone (dimension stone), crushed stone for road base, and common educational specimens for paleontology.

Geological facts

This specimen contains visible fossil impressions, possibly brachiopods or crinoids, which serve as 'time capsules' of ancient sea floors. It reacts vigorously (fizzes) with dilute hydrochloric acid.

Field identification & locations

Identify by looking for visible skeletal fragments or imprints of marine life within a gray, fine-grained rock. Use a drop of vinegar or acid to confirm carbonate composition.